Personality has become a major focus in organizational research, leadership development, derailment, and particularly employee selection. All pharmacists are not possessing personalities that are favorable to field being practiced and may not perform their best in and ultimately fail to perform their expected role in health care system. The present study was designed to assess the relationship between personality traits and job performance of pharmacists working in different fields in twin cities of Pakistan. A descriptive cross-sectional study design was used. Sample size was calculated to be 382 pharmacists to achieve 95% confidence level with 5% margin of error. A pre-validated data collection tool Big Five Inventory questionnaire was self-administered to the respondents while the performance of these 382 selected respondents was evaluated by using Performance Evaluation Questionnaire (PEQ) requested to be filled by their respective reporting managers. After data collection, data was cleaned, coded and analyzed using SPSS version 21. Results showed that relationship exists between all personality traits including extraversion, agreeableness, neuroticism, consciousness and openness with job performance. The present study concluded that a significant association exists between personality traits and job performance among pharmacists in Pakistan. Although, neuroticism a negative trait was found high among pharmacists but it was encouraging to notice that pharmacists also possessed positive traits including extraversion, consciousness and openness in their personality which was reflected as their good performance.