Generally speaking, there is decreasing return to scale in agriculture sector . This means a proportional change in all inputs causes a less than proportional change in output. When this exist, the small size of farm will be more efficient than large size from technical view .The main purpose of this study was determining the relation between returns to scale and the type of product. The necessary data was collected from a sample of 140 farmers in Kerman and then products were classified to corns, cereals , summer crops, forage and melon ground . The production function in transcendental form was estimated for each group of products by using SPSS program. Also the partial and total elasticity of output were computed for all inputs and every group of products . The study showed that, there was decreasing return to scale as a whole but this was not true for every individual product . In other words., there has been decreasing return to scale in production of cereal forage , and melon ground , but decreasing returns to scale in production of corns and summer crops , which means that these two products can be product more efficiently at large scale than small scale farmes.
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