OBJECTIVE: Evaluate the number of ethical and professional complaints involving obstetricians and gynecologists (OBGYNs) and the profile of the physicians denounced. METHODS: Retrospective descriptive study of all 4,138 ethical and professional complaints registered at the medical board of the state of São Paulo between January 1, 1994 and December 31, 2004. The following variables were collected: number of complaints involving OBGYNs, number of OBGYNS involved gender and age (< 30, 31 to 45, 46 to 60, > 60 years) of the physicians denounced, number of involved physicians with residence training (RT) and with specialist certificates (TEGO). The last four variables were compared with a control group of 8,466 OBGYNs practicing in the state of São Paulo who were not denounced to the state medical board. Data collected was submitted to statistical analysis. RESULTS: A total of 503 complaints (12.16%) involved OBGYNs and 781 OBGYNs were denounced. The majority of these physicians were male (599, 76.70%). Regardless of their gender, most physicians denounced (505, 64.66%) were under 45 years of age. Most of the OBGYNs denounced had no residence training (487, 62.36%) and were not board certified specialists (572, 73.24%). Other relevant variables were analyzed and will be presented in future publications. CONCLUSIONS: Between January 1, 1994 and December 31, 2004, 4,138 formal complaints were registered at the medical board of the state of São Paulo A total of 503 complaints (12.16%) involved Obstetrics and Gynecology and 781 OBGYNs were denounced. The typical profile of the physicians denounced was: male, under 45 years of age, without residence training and with no specialist certificate. This study was the first of a series involving the complex investigation of OBGYNs involved in ethical or professional complaints. These preliminary results pointed out deficiencies and important information that probably will be useful for the implementation of actions to improve the practice of obstetrics and gynecology and consequently reduce the number of complaints.