Despite their rich heritage and appealing past, the informal entrepreneurs are vulnerable at present with having less significance in the economy of Bangladesh. The study aims to explore the socio-economic functions and the factors influencing the sustainability of informal entrepreneurs in Bangladesh. The study applied the survey method using face-to-face structured interviews from 400 informal entrepreneurs from Dhaka, Gazipur, Tangail, Narayanganj, Sirajganj, Rangpur, Khulna, Chattogram, Cumilla and Brahmanbaria following cluster sampling, convenience sampling, snowball sampling and purposive sampling. Results in the study found that Socio-Economic Status of Informal Entrepreneurs in Bangladesh is vulnerable. By Conducting Data Normality Test, Chi square test, Pearson Correlation, Cronbach Alpha and Ordinal Logistic Regression, results show that economic and social indicators do not get achieved due to low earnings. The Data normality test indicates that the data are not normal as the p-values from the data normality test are less than 0.05. Based on Chi-square test (p>0.05), it was determined that informal entrepreneurs are mostly dissatisfied in terms of economic indicators whereas informal entrepreneurs are less dissatisfied in terms of social indicators. The study addressed major challenges like increasing cost of raw materials (83%), shortage of Capital (58.3%), inadequate loan support (47.5%), Unavailability of quality materials at the local level (45.5%), product spoilage (23.5%) and, not adequate space for work (12.8%) that hinder the sustainability of the informal entrepreneurs. The findings of the study will be quite informative for the government administration, local government, GO-NGOs for working for the betterment of informal entrepreneurs and also for the social researchers, academicians for further study in future.