In order to assess the factors that affect the success of entrepreneurs of small and medium sized enterprises of Bangladesh, survey data were collected from eighty entrepreneurs from the southern region of Bangladesh selected through random sampling technique. Success factors here refer to demographic characteristics and environmental factors that impede the business success of entrepreneurs of small and medium-sized enterprises of Bangladesh. The results indicate that that the success of the entrepreneurs was correlated to all independent variables in the study and all hypotheses were supported. Lack of infrastructure, sound political environment, access to market and capital were the major factors that positively hindered the success of the entrepreneurs. Experience and education were positively correlated while age was negatively correlated to success. The regression models fit for regression equations were determined by F statistics. The models indicate positive and statistically significant relationship. Altogether demographic variables explained 26.9% of the total variance in Business and Economic Research ISSN 2162-4860 2013 www.macrothink.org/ber 39 success while environmental variables explained 39.8% of the total variance in success.