Introduction: Valproic acid (VPA) is one of the commonly used anti-epileptic drugs. It is also an effective mood stabilizing drug. Despite its therapeutic benefits, hematological toxicity of valproic acid is increasingly encountered. Therefore, this study was carried out to evaluate the various hematological changes in adult patients on VPA and to closely monitor them so as to prevent the life threatening side effects of VPA. Aims and Objectives:(1) To study the spectrum of hematological changes in adult patients on VPA therapy and its distribution in different age groups and sex. (2) To establish a correlation between the dosage and duration of VPA therapy and its hematological effects. Materials and Methods: The present study was a prospective study done over a period of one year. A total of 50 adult patients on VPA therapy for atleast six months duration and attending the out -patient department (OPD) in General hospitals under the Bangalore rural district were included in the study. Results: A total of 50 adult patients on VPA therapy were included in the study. The patients were categorized into different age groups and sex. Female to male ratio was 2.6:1. Females constituted 72% of the total number of cases. The majority of the patients were in the age group of 26-35 years constituting 36% of the total number of cases. The spectrum of hematological changes were isolated anemia (8%), isolated leucopenia (4%), isolated thrombocytopenia (28%), bicytopenia (28%) and pancytopenia (24%). A direct correlation was established between the dosage as well as the duration of VPA therapy and the hematological changes observed especially in the elderly females. A significant negative correlation was found between the dosage of VPA therapy and the platelet and leucocyte counts. Conclusion:The study helps in identifying the potential risk factors, closely monitoring the patients on VPA and preventing life-threatening side effects. It also helps the clinicians in dose adjustments and sensitizes them to be cautious while prescribing VPA in higher doses and for longer duration.