The Farmer Field School (FFS) approach has been tried widely and has created positive impact on crop and soil productivity in many Asian and African countries. Kenya Agricultural Research Institute (KARI) introduced FFS approach in the year 2001 as an alternative to conventional approach to promote dissemination of Soil and Crop Management Technologies (S&CMTs). The purpose of this study was to determine the impact of Crop Management technologies (CMTs) disseminated through Farmer Field Schools (FFSs) on maize productivity among the smallholder farmers in North Rift, Kenya. Eight technologies were scaled-out using the approach and the conventional extension methods. A survey methodology with an Ex-post facto research design was used with a sampling frame consisting of 6,560 small-scale farmers. A sample of 180 FFS and 180 Non-FFS farmers was chosen for the study, using proportionate stratified random sampling. Data was collected through interview schedules administered to FFS and Non FFS farmers. Descriptive statistics was used to compute percentages, means and standard deviations. One way ANOVA was used in the study. The results of ANOVA indicated a statistically significant difference between the means of the groups (F=94.320, df =2, p=0.000). Therefore, the null hypothesis four was rejected. It was concluded that there was a statistically significant difference in the means of the two groups. By subjecting the results to further post hoc multiple comparison analysis, the results indicate that there was a statistically significant difference in the means of the FFS participants before and after FFS participation (p=0.000) and also between the Non FFS participants and the Participants after FFS training (p=0.000). The main recommendation from this study was therefore, the need to scale-up and scaling out the S&CMTs using the FFS approach in counties in the North Rift region of Kenya.