Drugs are considered highly essential and sensitive items for saving lives. Pharmaceutical sector in Bangladesh has grown from strength to strength over the last 40 years and evolved from an import dependent to self-reliant, export oriented sector. But counterfeit, adulterated and sub-standard drugs, though small in percentage, still remain to be a threat in the local market. This cross sectional study was conducted during March to September 2016, with the purpose of this study is to determine potency of some essential drugs, which were used vigorously by sub-urban and rural people and manufactured by randomly selected small and medium pharmaceutical industries of Bangladesh. The study revealed that the measured potency of different essential drugs manufactured by randomly selected small pharmaceutical industries was mostly unsatisfactory.