Introduction: Long-acting depot injections of antipsychotic medications are an important way to monitor treatment noncompliance in patients suffering from schizophrenia. Pain and discomfort at the injection site may result in patients' refusal of depot injections. The present study is a pilot study that attempts a systematic characterization of injection site pain. Method: Thirty-four consecutive outpatients suffering from DSM-IV - defined schizophrenia or schizoaffective disorder and treated with depot antipsychotic medications were evaluated. The pain they suffered from the injections was quantified using a visual analog scale. This evaluation was made 5 minutes before the injection, 5 minutes after, 2 days after, 101 days after, and before the next injection. Patients were also administered a modified version of the Rating of Medication Influences scale that included a specific question on the possible relationship between injection-associated pain and future compliance to depot treatment. Results: The depot injections cause pain, which is maximal immediately after the injection, declines substantially 2 days after, and disappears by the tenth day after the injection. A correlation exists between reported injection site pain and the effect it has on patients' attitude toward the depot injection as reported by the patients. Zuclopenthixol depot injection is more painful than other depot medications. Conclusion: Depot injections are painful. The pain they inflict has a typical course, and medication type is among the factors that influence this pain. This pain might have an effect on patients' attitude toward depot injections and thus is of importance in the management of patients suffering from schizophrenia.