Related-party transactions (RPTs) are usually dual in nature since they fulfill the economic needs of the firm while at the same time, they serve as mechanisms through which the resources of firms are manipulated, exploited and diverted. This paper takes cognizance of both aspects by investigating the relation between transactions deemed to have taken place by related parities and the financial health/position/performance of Nigerian firms. The financial health/performance parameters of concern to this study are Return on Assets (ROA), Return on Equities (ROA) and Earnings. The expost-facto design was employed and performance data were sourced from the financial reports/statements of sampled firms during the period 2007 – 2014. The data so obtained were analyzed by the simple regression technique. The insinuation from our findings is that transactions deemed to have taken place by related parties are not significant, and are not correlated with financial performance. We also found no proof of cause-effect link amid such transactions and the performance measures adopted by this study. On this note, we recommend a stern regulation of transactions that are deemed to have taken place by related parties in Nigeria. It is believed that this would discourage their non-transparent use especially in the area of earnings manipulation.