The study investigated the relationship between employees heterogeneity and the performance of United Cement Company Limited, (UNICEM) Calabr, Nigeria. The specific objectives of the study were to evaluate the extent to which proxies of workforce diversity such as; Religious, and ethnic diversities respectively affect the performance of UNICEM. Relevant conceptual and empirical reviews were conducted and the theoretical framework of the study was anchored on organizational theory by Mary Parkelfollet. Descriptive research design was used for the study. 400 employees of UNICEM constituted the population of the study, from which a sample of 196 was carved out with the aid of Krejcie and Morgan Table. A structured and validated Questionnaire was used to gather relevant data from the respondents and data was analysed and the null hypotheses tested with Pearson Product Moment Correlation analysis. The result revealed that UNICEM adopted the principle of Equal Employment Opportunity, devoid of ethnic discrimination. Results also revealed that employees of diverse religions in UNICEM perform their duties creditably in similar manner. Recommendations were also adduced, which included the fact that sensitive organizational activities should be organized in a manner that is all inclusive of employees of diverse ethnic divides and religions in UNICEM.