This study assessed the effect of financing decisions on operational performance of pharmaceutical firms in Nigeria. Three variables: Long Term Debt (LTD), and Short Term Debt (STD) were regressed against the dependent variable: Turnover (TNV). Haussmann test was conducted to choose between Fixed Effect and Random Effects model. Results justified the use of Fixed Effect model. Test results indicate: positive but non-significant contributions of Long Term Debt (LTD) on the Turnover (TNV); and Short Term Debt has positive and significant contribution on Turnover (TNV) of pharmaceutical firms in Nigeria. Based on the findings of the study, the researchers conclude that firm needs to choose a suitable financial decision at certain proportion to be better off and recommends that it is important for corporations to retain much of their profits for re-investment as this will make funds readily available to them and avoid the problem of working capital shortages. This will equally enhance efficiency and productivity, expansion and diversification and even automation and modernization.