Capital structure has been engrossed with a lot of attentions and still lingers as a source of controversies among researchers and academia. To this end, this study examined the influence of capital structure on firm performance with evidence from selected quoted firms in the pharmaceutical industry in Nigeria over the period of 2009 to 2017. The study adopted the panel regression analysis with dependent variables proxied financial performance as return on asset (ROA) and return on equity (ROE), while independent variables are debt to equity ratio (DER), long term debt ratio (LDR), short term debt ratio (SDR), total asset (SIZE) and inflation rate (INF). The fixed effect results in the two models indicate that only firm size was significant and negatively connected to pharmaceutical firms’ performance using return on asset. From the outcomes, there is evidence of no significant rapport between capital structure and performance of firms in the pharmaceutical industry in Nigeria. However, the significance of the two models adopted connotes that there are other variables outside the models that predict performance in the pharmaceutical industry, these variables can further be explored by other researchers. However, based on the findings from the study, it was recommended that, pharmaceutical firms should be cautious with their funding mix.

Keywords : Capital structure, Debt, Equity, Financial Performance.