The aim of this study is to assess the effect of interest rates on the financial performance of SMEs in urban informal settlements in Kenya. This study adopts the descriptive survey design. Data were collected from 120 SMEs in the 6 wards of Mathare Sub-County. Data was collected using semi-structured questionnaires. It was analysed using descriptive and inferential statistics. The findings show that low-interest rates could influence the propensity of SMEs to apply for these loans. The ability to pay mobile loans without problems due to low interest rates enhanced the performance of the respondents’ businesses. This goes on to contribute to poverty alleviation in urban informal settlements through enhanced access to capital; one of the goals of the world bank. This has further ripple effects since it can contribute to income diversification for the inhabitants of poor urban areas. The following recommendations were made. The government should also reduce interest rates to lower the cost of mobile phone interests as well as the interest rates of other loan products. Mobile loan lenders should also ensure that their loan products are affordable for the urban poor.