The Federal Ministries in Nigeria harbor human resources whose potentials are underutilized. This problem emanated from mismanagement of workplace diversity which is the differences in ethnicity, skill, age and ancestry. In pursuit of the problem, the study sought to determine the extent to which workplace diversity is managed in the Federal Ministries for enhanced service delivery with specific focus on ethnic diversity and team creativity; skill diversity and innovative capability. Research questions and hypotheses were formulated in line with the objectives. The study is built on theoretical foundations of Social Categorization and Social Identity propounded by Tajfel and Turner in 1986. Correlational research design was adopted for the study and five Federal Ministries were randomly selected. Pearson Product Moment Correlation was used to test the hypotheses. The study revealed clearly that positive relationship exists between ethnic diversity and team creativity. For the hypothesis two, there is no positive relationship between skill diversity and innovative capabilities of the employees in the Ministries. These imply that ethnic diversity enhanced team creativity but skill diversity did not enhance innovative capabilities of employees in the Ministries. The study recommended that efforts should be made by the Federal Government to promote institutions and policies that are likely to reflect cross cutting cleavages and encourage nationalism, as opposed to narrow, tribal and ethnic dimensions.