Introduction: The aim was to report the occurrence of after application of olanzapine long-acting injection (OLAI) in patients with schizophrenia during one year period. Subjects and methods: During one year period, OLAI was applied to 30 patients with schizophrenia (18 men, 12 women) who were non-adherent to previous treatment with oral olanzapine. Patients were 20-58 years of age (39 years old on average), diagnosed with SCID based on DSM-IV-TR criteria. Patients received OLAI in dosage between 210-405 mg (287±62 (mean ± SD)) every 2-4 weeks. Results: Out of 30 patients that received OLAI, 29 patients improved significantly without side-effects, and one patient developed post-injection delirium/sedation syndrome (PDSS). The patient's somatic condition stabilized and treatment with OLAI was discontinued due to the PDSS. Conclusion: The occurrence of PDSS is not common and when it occurs, in our experience, it was reversible.