Background: Access to free diagnoses and treatments has been shown to be a major determinant in malaria control. The Cameroonian government launched in February 2011 the exemption of the under-fives' simple malaria treatment policy. This study aimed at assessing the main effect of the policy on services utilization. Methods: A concurrent mixed-method research using time series data collected in July 2011 and April 2012, and qualitative data collected in April 2012 was conducted. Content analysis was used for the qualitative data. For the quantitative data, a proxy was used to measure living standards by calculating a composite index using principal component analysis. Results: General outpatients consultations and of the under-five (U5) increased to about 10% during the year 2011 compared to the year 2010 (before the policy). The average number of consultations for simple malaria cases in children U5 increased in the months following the launch of the policy then started declining from September 2011. The proportion of U5 who was exempted from payment of drugs increased from 19.6% to 32.9% at 4 and 12 months after the implementation of the policy. In contrast there was no effect in reducing inequalities among socioeconomic groups: the rural and lowest socio-economic households benefit less from the exemption measure (RR respectively 2.7, 1.6). Two thirds of U5 who used health services for uncomplicated malaria paid on average 2940 FCFA (6 $USA) for the treatment. The major part of this cost was made on the acquisition of artemisinin combination therapy (1680 FCFA/3.5 $USA).