Medical records are commonly used to measure quality of care. However, little is known about how accurately they reflect patients' clinical condition. Even less is understood about what influences the accuracy of provider's documentation and whether patient characteristics impact documentation habits. Discrepancies between symptoms and side effects evaluated by direct assessment and medical records were examined for 224 patients with schizophrenia at two public mental health clinics. Multivariate regression was used to study the relationship between patient, provider, and treatment characteristics and documentation accuracy. Overall, documentation of symptoms and side effects was frequently absent. Documentation varied substantially between clinics, and it was generally less likely for patients who were severely ill, black, or perceived as noncompliant. The accuracy and consistency of medical record documentation should be demonstrated before using it to evaluate care at public mental health clinics.