BACKGROUND: Data registered in health facilities about malaria are vital source of information regarding the trend and pattern of the disease. Moreover the data also used to evaluate the impact of the intervention methods and to plan malaria control accordingly. The aim of this study was to assess the number of malaria cases in the service providing health institutions of South Omo Zone, SNNPR, over a period of seven years, 2008-2014. METHODS: A retrospective review of routinely collected and recorded data on malaria was conducted at Hana and Keyafer health centers located in South OmoZone, during December-March/2014. RESULT: This retrospective study examined records of 54,160 presumptive and confirmed malaria cases registered over seven years (January 2008-December 2014). Among the registered, a total of 22,494 laboratory confirmed malaria cases were reported. The mean annual prevalence of malaria was 3213, with total slide positivity rate (SPR) of 41.53%. The seven years' overall trend of malaria occurrence in the study sites showed a fluctuating trend from 2008 to 20114. P. falciparum was the predominant species with no trend shift in seven years period. Plasmodium falciparum accounted for 61.03% and Plasmodium vivax for 32.44%. Most of the confirmed cases were males (63.26%) and most were above 15 years old (70.7%). Rainfall at lag of one month was significantly predicting number of cases at Hana Health center (P< 0.001), though it was found to be not significant in case of Keyafer Health Center. CONCLUSION: The finding of the retrospective study revealed that malaria still remains as a public health problem in the study areas. The deadly species P. falciparium was most predominant, and the age group above 15 was more infected. Hence, malaria intervention methods should be scaled up in the study sites.