OBJECTIVE Evaluate and correlate individual, work-related and organizational factors that influence adherence to standard precautions among nursing professionals of psychiatric hospitals in São Paulo. METHODS An exploratory cross-sectional study conducted with 35 nursing professionals, using the assessment tool for adherence to standard precautions through the Likert scale, ranging from 1 to 5. RESULTS Knowledge of the precautions received a high score (4.69); adherence received (3.86) and obstacles (3.78), while intermediaries and the scales of organizational factors received low scores (2.61). There was a strong correlation between the magnitude adherence scale and the personal protective equipment availability (r = 0.643; p = 0.000). The training scale for prevention of HIV exposure (p = 0.007) was statistically different between the nurses and nursing assistants. CONCLUSIONS The organizational factors negatively contributed to adherence to standard precautions, indicating that psychiatric institutions lack safe working conditions, ongoing training and management actions to control infections.