Residual schizophrenia is a type of schizophrenia with a record of at least one psychotic episode, followed by symptoms that are more prominently negative. Antipsychotic use is the primary therapy, but long-term antipsychotic use affects problems such as Adverse Drug Reactions, resulting in reduced adherence, relapse, and poorer quality of life. This study aims to identify the cases of adverse drug reactions using antipsychotics in Residual Schizophrenia patients in the Outpatient Installation of Purworejo Hospital, Central Java, Indonesia. This study is a non-experimental study with descriptive analysis with prospective data collection from October to November 2020. Data were collected through direct interviews employing the Naranjo Scale instrument to assess symptoms and medical record data to observe laboratory values. Data analysis used univariate analysis with the descriptive test on the SPSS programmed version 16.0. The sample of this study was schizophrenic patients aged ≥ 18 years and receiving antipsychotic therapy for at least one month, while the exclusion criteria were patients with low adherence levels, and patients receiving metoclopramide therapy. This study obtained a sample of 97 patients. Most of the patients received treatment with Haloperidol + Clozapine 37.1%, Risperidone + Clozapine 10.3%, and Clozapine 10.3%. The highest cases of adverse reactions were in the use of Haloperidol with tremor 36 (24.66%), rigidity 16 (10.96%), akathisia 15 (10.27%), and bradykinesia 6 (4.411%), weight gain 11 (7.53%), dyskinesia tardive 2 (1.37%), acute dystonia 2 (1.37%), and erectile dysfunction 1 (0.68%). Studies related to the side effects of antipsychotic use in patients with residual schizophrenia mostly occur with haloperidol with various effects, one of which is an extrapyramidal syndrome, weight gain, and erectile dysfunction. Thus, the role of pharmacists is very much needed in monitoring antipsychotic drug therapy related to side effects to achieve drug effectiveness in the success of therapy.