The use of devices that emit radiofrequency electromagnetic fields (RF-EMF), such as mobile phones, has arisen rapidly in recent years. With increasing usage of mobile phones, public concern about possible adverse health effects from exposure to mobile phone signals have occurred. The results of many studies have shown that exposure to radiofrequency radiation at the operating frequency of mobile phones can induce various biological effects in different species. One of the major effects could be possible genotoxicity and oxidative stress. However, it is very important to emphasize that the mentioned effects of RF-EMF are still controversial because there are several studies that have not found biological effects after exposure to RF-EMF or have some shortcomings, especially in genotoxic effects. Previous studies regarding effects of RF-EMF at frequencies from 900 MHz to 2.4 GHz in honey bee colonies investigated mostly adult honey bees in unnatural conditions i.e. after direct exposure to the mobile phone handset. Although few studies found no effect on aggression and navigation of honeybee, brooding, honey production and foraging behavior, the majority of results have shown effects such as decreased colony strength and egg laying rate of the queen, induction of “worker piping” which is associated with swarming and the alteration of some biochemical parameters (total carbohydrates, glucose, glycogen, total lipids, cholesterol, protein, hexokinase, alkaline phosphatase, glucose 6-phosphatase and free amino acids) in the hemolymph of the drone. However, there are still many uncertainties and controversies about the effects of RF-EM radiation in honey bee. Furthermore, the results of some experiments suggest that radiation produced by mobile phone base station towers is actually frying the navigational skills of the foragers and preventing them from returning back to their hives, and there are some reports of sudden unexplainable disappearance of adult honeybees, syndrome called Colony Collapse Disorder (CCD). In the light of mentioned literature data, the aim of this study was to investigate the oxidative stress parameters and genotoxicity in honey bee larvae, pupae and adult bees after long-term exposure in nature condition as well as short-term exposure to RF-EMF under controlled laboratory conditions at the operating frequency of mobile phones with different field levels and modulation. Next, aim of this study was to determine some behavior patterns regarding biological-rearing status, strength of honey bee colonies, situated at different distances from two mobile phone base stations, in field conditions. Fifteen honeybee colonies (A. mellifera) were selected, and situated at three locations in nature: O (n═5; 65,41 m and 159,46 m distance from mobile phone base tower, respectively); H (n═5; 790 m and 700 m distance from mobile phone base tower, respectively); K (n═5; 1630 m and 1520 m distance from mobile phone base tower, respectively). Before transportation of hives with honey bee colonies to selected locations the average frequency and electric field level were measured at each location using power density meter NARDA SRM 3000 (NARDA, USA). Under laboratory conditions exposure of honey bee larvae to a homogeneous electromagnetic field was carried out in the Gigahertz Transversal Electromagnetic Cell. The four to six days old honeybee brood in original combs were exposed to continuous radiofrequency electromagnetic field (RF-EMF) and modulated signal (80% AM 1 kHz sinusoidal) at frequency of 900 MHz and field level of 10, 23, 41 and 120 V m-1 for 2 hours. All antioxidant parameters such as catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST) as well as lipid peroxidation (TBARS) were measured spectrophotometrically. Genotoxicity was mesuared using alkaline Comet assay (single cell gel electrophoresis assay) while few clinical inspections of honeybee colonies were conducted to recorde biological aspect: colony strength - the total area under honeybee brood and comb surface covered with adult bees was measured according to Liebefeld method; presence of queen cells on combs; and aggressiveness as well as composure as rearing parameters. Under laboratory conditionsthe GST activity in the honey bee larvae exposed to unmodulated RF-EMF at frequency of 900 MHz and field levels of 10, 23, 41, 120 V m-1 was not statistically different when compared to the control. The lowest GST activity was measured in the larvae exposed to modulated (80% AM 1 kHz sinus) field at 23 V m-1, and it was significantly lower than in the larvae exposed to unmodulated field at 23 V m-1. The CAT activity was significantly decreased in the honey bee larvae exposed to unmodulated RF-EMF at field level of 10 V m-1 when compared to control group, as well as with group exposed to unmodulated RF-EMF at field level of 23, 41, 120 V m-1 and modulated (217 Hz) field at 23 V m-1. The SOD activity in the honey bee larvae exposed to RF-EMF at frequency of 900 MHz and field levels of 10, 23, 41, 120 V m-1 was not statistically different compared to control. However, the lowest SOD activity was measured in the larvae exposed to unmodulated RF-EMF at field level of 10 V m-1 and it was significantly lowerthan in the larvae exposed to a modulated (217 Hz) field at 23 V m-1. The TBARS concentration was significantly decreased in honey bee larvae exposed to unmodulated RF-EMF at a field level of 10 V m-1 when compared to the control group. Although the content of TBARS in all other exposed groups was lower than in the control group, there was no significant difference between the groups. DNA damage was significantly increased in honey bee larvae exposed to modulated (80% AM 1 kHz sinus) field at 23 V m-1 in comparison to the control and all other exposure groups. Other treatments did not trigger significant DNA damage in comparison to the control. Under natural condition the results showed that the activity of antioxidant enzymes as well as lipid peroxidation concentrations depend on the stage of bee development, sampling site, and seasonality. The most significant differences in honeybee colonies behavior, as well as in biological parameters, was observed during first two months after colonies exposure and changes were visible only for colonies situated at location at nearest distance from mobile phone base tower. The results suggest that RF-EMF effects in honey bee larvae appeared only after exposure to a certain EMF conditions; they did not follow a linear dose-response relationship and they strictly depended on the measured parameters, field levels and modulation. Modulated RF-EMF produced more negative effects than the corresponding unmodulated field. Next, it is important to emphasize that RF-EMF at 900 MHz, which is used in GSM communication and is modulated at 217 Hz, did not cause any statistically significant changes in all observed parameters in cases when their results were compared to the control group. But, despite this, the modulation at 1 kHz showed the increase of DNA damage. Likewise, it can be concluded that exposure of honeybee colonies in vicinity to mobile phone base stations in field conditions, as unfavorable environmental factor, may induce alteration in the honeybee behavior and biological activities, probably as adaptation process consequence.