The objective of this study is to analyse the effect of formalization on the performance of SMEs in Cameroon. Statistical analysis and the multiple regression model are used. Statistical analysis shows that the fact that a company is formalized increases its probability of improving its performance, since this probability increases from 6.03/10 when it is informal to 7.09/10 when it belongs to the formal sector. Besides, the positive influence of formalization on performance is confirmed by econometric analysis.