Humanitarian assistance continues to assist Rwandan refugees who select to voluntarily repatriate their children. Mahama camp experienced clean water supply which was below standards (at an average of 13.8 liters per person per day as compared to the standard of 20 liters per person per day), there was a lack of school facilities (60 students per classroom), and there were recurrent challenges in maintaining the provision of food assistance, land scarcity resulted in the congestion of refugee camps and limited opportunities for agricultural projects, and reduced support for self-reliance activities, with under 17,000 refugees engaged in income-generating activities during the year. Therefore, they are often very reliant on overseas aid, now they are no longer capable to enhance their resilience skills or preserve support livelihoods. Therefore, this study examined the effect of humanitarian assistance for vulnerable communities on social welfare of refugees in Rwanda. The specific objective of this study was to examine the implementation of humanitarian assistance for vulnerable communities in Mahama Refugee Camp; to assess the satisfaction level in refugees’ welfare and to identify weaknesses in the acquisition of basic needs in Mahama Refugee Camp. The descriptive (quantitative and qualitative) and analytical research design was used in this study; the sample size is 100 respondents from 54000 population and using simple random sampling techniques. The data collected was coded and Statistical Package for Social Science (SPSS) version 20 was used for data entry and analysis, statistical tools were used including frequency counts, percentages, mean and standard deviation. The implementation of humanitarian assistance for vulnerable communities by 4.15 of overall mean, the satisfaction level in Refugee welfare by 4.12 of overall mean and the weaknesses in acquisition of basic needs by 2.9 of overall mean. As recommendation, they should provide way of solving same challenges such as food security, security and water and sanitation. Keywords: Humanitarian Assistance, Vulnerable Communities, Social Welfare, Mahama Refugee Camp, Rwanda