Farmer Field School (FFS) always aims to facilitate farmers about field ecology and integrated crop management. The study was conducted in 2012-13 to analyze the activities of Farmer Field School approach, interaction of extension personnel/facilitators with farmers and adoption ratio of FFS approach. It also investigates the different stages of crops and their associated management practices and to determine increase in per acre yield of the crop and profit maximization margin per acre. A study of bitter gourd crop was conducted in ten villages of district Charsadda and the study of tomato crop was conducted in ten villages of district Malakand. Fifteen farmers were selected randomly from each village on the basis of 60% of FFS population and making sample size of 300. Both primary and secondary data were collected from farmers and department of agricultural extension respectively. Structured interview schedule was developed and each farmer was interviewed personally. The study was based on comparison of cost, yield and income of bitter gourd and tomato before and after FFS. Paired t-test was conducted using SPSS for analysis. Result of the study show that agricultural extension department has brought a positive change in the attitude of farmers through FFS approach. About 69% of the respondents were growing bitter gourd in Charsadda between the ages of 31-50 years, Majority 77% of respondents was literate and 23% were illiterate. Average land holding size was 9.89 acres; Cost of fertilizer, crop protection from insect pest and crop protection from diseases was reduced by Rs. 2264.17, Rs. 3379.97and Rs. 3181.19 respectively. The cost of seed and cost of farm yard manure was increased by Rs.1923.07 and Rs. 1204.66 respectively while bitter gourd yield was increased by 988 Kg/acre from 17384.60 to 18372.60. In district Malakand66% of the respondents were between the age group of 31-50 years, 58% of respondents were literate while 42.0% were illiterate. Cost of seed, crop protection from insect pest and crop protection from diseases was reduced by Rs. 210.67, Rs. 2592.10 and Rs. 3127.98 respectively. The cost of fertilizers and cost of farm yard manure was increased by Rs.1548.87 and Rs. 1151.33 respectively, while tomato yield was increased by 1585.03 kg/acre from 7663.87 to 9248.90 kg/acre. It is concluded that empirical activities of FFS approach is not only beneficial and useful but enhanced the agricultural productivity. Interaction of extension agents with farmers increased awareness and propagated 11 new technologies related to tomato and bitter gourd resultantly improved the socio-economic conditions of farmers. It is recommended that extension department should extend developmental activities through participatory FFS approach. Trainings, seminars and refresher courses should be arranged for both FFS facilitators and farmers.