Abstract: Boosting the micro enterprises (MEs) sector of the economy has featured consistently in the agenda of successive policy makers in Nigeria in recent times. In line with this concern, development planners have gone ahead to identify a key factor to achieving the desired results - steady supply of public electricity. This is because MEs in Nigeria depend very much on public electricity to function. Unfortunately, public electricity supply in Nigeria currently is below capacity, meeting neither the demands of the Nigerian public nor those of organizations including MEs. Using the Social Disorganization Approach of the Functionalist Theory, this study analyzes the challenge of fluctuation in public supply of electricity and examined its impact on the sustainability of MEs in the Southern Senatorial District Cross River State, Nigeria. With the help of the questionnaire, data for the study were generated from 340 operators of MEs in the study area. Using percentages, responses to questionnaires items were analyzed while the Z statistical technique was utilized to test the hypothesis of the study. Results unveiled among other issues that fluctuation in public supply of electricity has a significant negative impact on the profit margin, and consequently, the growth and sustainability of micro enterprises the Southern Senatorial District of Cross River State, Nigeria.