Day surgery and ambulatory surgery are two modalities of outpatient treatment carried out in day surgery department in Croatia. The purpose of this study, conducted in day surgery department, was to collect and analyze indicators of patient structure, diagnoses, performed procedures and organization of ambulatory surgery. This study analyzes 3409 ambulatory procedures and histological diagnoses of removed tissue in 2736 patients (1457 female and 1279 male). The indications for treatment were in 408 (14.9%) cases set by dermatologists while others were referred by primary healthcare physicians. According to the referral diagnosis, 2522 (92%) patients had benign, 47 (2%) dysplastic, and 167 (6%) malignant changes. The average patient age was 52.8 years. Patients with benign changes were, in average, significantly younger (44.2) than those with malignant ones (66.5). The most common referral diagnosis was D-22 melanocytic nevus. From a total of 38, 10 most common diagnoses constitute 87% of all referral diagnoses. According to International Classification of Diseases, Tenth Edition (ICD-10), these are: D22 (33.9%), D23 (21.3%), D21 (13.4%), D17 (6.9%), D21.0 (3.2%), C44 (2.4%), D21.1 (1.7%), L02 (1.6%), L08 (1.6%), B07 (1.3%). The main surgical procedures include extirpation, excision and biopsy of pigmented changes or skin neoplasms. When a procedure was performed because of a suspected benign lesion, pathohistological diagnosis confirmed 94.6% of such referral diagnoses as benign, whereas only 48% of clinically suspected malignant neoplasms were pathohistologically malignant. Out of patients referred with a clinically diagnosed benign lesion, 114 (4.5%) patients had a pathohistologically confirmed malignant skin tumor. The total number of malignant neoplasms was 219 (8.0%), and of melanoma 24 (0.8%). Out of 16 anatomical regions of the human body surgical procedures performed in three localizations make 56% of all localizations of performed procedures. These are: back (750), head (520) and chest (260). The procedures were performed by 22 physicians of various specialties, mostly by general surgeons (64.2%). Plastic and reconstructive surgeons performed 458 (16%), pediatric surgeons 381 (13.9%) and others 130 (4.8%) procedures. Ambulatory surgery is the surgery of skin, subcutaneous and soft tissue, usually affected by benign tumors or pigmentary changes, located mostly on the head and trunk. Only 43.8% of patients with verified malignancy were clinically recognized, which indicates, along with the higher incidence of malignancy in pathohistological (8%) than referral (6%) diagnoses, that a significant number of patients did not undergo a thorough diagnostic procedure.