Lung cancer is a major public health problem in Croatia and in the world. In Croatia, lung cancer is the second in frequency and the first in mortality with age-standardized rates of 47.2 per 100,000 for incidence and 41.8 per 100,000 for mortality. This research aimed to examine whether the diagnostic period of patients with a working diagnosis of lung cancer differs depending on gender, the presence or absence of symptoms, and with regard to the year of diagnosis and changed working conditions in Zagreb hospitals. A total of 426 subjects were divided into two groups depending on the year of diagnosis (2018 and 2022), and within the group into symptomatic and asymptomatic. In asymptomatic patients, the time from the accidental finding of a suspected lung neoplasm by radiological treatment of another condition/disease to the biopsy procedure with the aim of pathohistological diagnosis was observed. In symptomatic patients, the time from the onset of symptoms to the first examination by a pulmonologist and the total diagnostic processing time from the first examination by a pulmonologist to the biopsy procedure were observed. A statistically significant difference was observed between the duration of diagnostic processing of symptomatic women and men in 2018 (p = 0.019) and in 2022 (p = 0.050), whereby the time from the first examination by a pulmonologist to the biopsy procedure was significantly longer in women than in men. Additionally, all diagnostic time intervals were longer in 2022 compared to 2018, which could be explained by the consequences of the COVID-19 epidemic and the condition of the Zagreb hospital after the earthquake. In contrast, in 2022, the time interval from the appearance of symptoms to the first examination by a pulmonologist was shorter than in 2018, which speaks in favor of better patient symptom recognition, patients' earlier contact with their family medicine doctor, as well as shorter time required until the first specialist examination.