The SMEs sector contributes so much to economic growth and this has immersed a lot of expectations by the economy of developing countries on the SMEs sector. The purpose of the study is to investigate the negative impact of high inflation on small and medium enterprises in Thika, Kiambu County Kenya. To achieve this, the study was guided by one general objective which was determining the effect of inflation on small and medium enterprises. The study general objective was to investigate the influence of inflation on SMEs performance. The study specifically narrowed down to; determine the influence of purchasing power, cost of borrowing and direct investment on SMEs performance. The study was based on Keynesian theory on a classical economy, Quantity theory and Mark-up theory. The theories related well with the study variables. The study adopted a descriptive research design, where the target population comprised of 50 individuals in top management, departmental staff and supervisors. The sample of 40 individuals was selected representing 80% of the population. Statistical Software for Social Sciences was used in the data analysis. Qualitative data was analyzed through content analysis. Quantitative data was analyzed through the use of descriptive analysis which includes: frequencies, percentage, means, standard deviation as well as multiple linear regression models. Study findings indicated that inflation has a significant relationship to SMEs performance as indicated by the three variables; purchasing power, cost of borrowing and direct investment. The study recommends that the top management of a business can use the study to know on how best to run the business operations. Direct investment was recommended by the study since it favored efficiency in the business operations