Objective: The present study aimed at finding out the personality factors that are associated with drug addiction. Methodology: It was a quantitative research design, descriptive study and was carried out at department of Psychiatry Military Hospital Lahore from June 2013 to March 2014. Sixty patients admitted in Psychiatry Department Lahore with diagnosis of mental and behavioural disorder due to psychoactive substance abuse were selected by purposive sampling technique. Patient's diagnosis was made on ICD-10 criteria. Assessment of personality factors were done by using The 16 Personality Factor Questionnaire. Data was analysed by using SPSS version 18 and descriptive statistics were used. Results: Results revealed that some sample scored high on two personality factors that were vigilance (61.66%) and apprehension (65%). This sample scored low on reasoning (68.33 %) and emotional stability (71.66 %) as well. Conclusion: Low emotional stability, low reasoning, over vigilance and apprehension are significantly associated with psychoactive substance use. The findings have preventive and therapeutic implications.