Background: Tramadol is an opioid analgesic indicated for the management of moderate and severe pains. Its side effects, in parts are due to the activation of µ receptors and in parts to increasing central catecholamine and serotonin levels. In the case of long administration, tramadol has a potential to cause dependency, tolerance and also drug abuse. After prohibition of injective diclofenac, considering Iranian’s tendency for rapid sedation of pain symptoms, tramadol has been prescribed widely. The aim of this study is to determine general practitioners knowledge about this new drug. Method: This cross-sectional study was arranged by collecting data through a self-administrated questionnaire consisted of 25 questions related to different aspects of drug knowledge. Sample consisted of 244 general practitioners in Kerman and data analysis was performed by SPSS. Results: Out of 173 general practitioners, 49.1% worked in clinics, 34.9% in private offices and 16% in Emergency Units. Mean knowledge score was 30.72+ 0.35 out of the maximum of (50). From all subjects 49.7% had poor knowledge (Z<-1), while 39.3% had moderate knowledge (-1<z<1) and="" 11%="" were="" sufficiently="" informed="" (z="">1). The poorest information was in regard to drug classification and pharmacokinetics, while in dosage and side effects subjects' knowledge was better. No correlation was observed between mean score and variables of job experience, duration, place and sex of practitioners. Conclusion: Considering serious side effects and drug interactions of tramadol and also the low level of knowledge of general practitioners about this drug, educational programs and limitation of distribution seems to be necessary.