This study was conducted to determine laminitis prevalence and evaluation of production and economic loss resulting to this disorder with use 100 Holstein cows in summery season. Cows distribute in 3 groups, High (H), Mild (M) and Low (L) producing with milk yield of 35 (SD 4.2), 26 (SD 3.6) and 18 (SD 3.4) kg and total number of cows in each group 26, 52 and 22 cows, respectively. Locomotion scores determined within each group with use back line and gait characteristics according to Sprecher's method. In this method, cows divided to 5 score where a score 1 show a cow that walks normally and a score of 5, a cow that is 3-legged lame. Scores 2 and 3 settled in subclinical and scores 4 and 5 considered to represent clinical group. Decrease of milk production and economic loss resulting to laminitis determined by Loss Calculator Software. Results indicated that the most number of normal; subclinical and clinical dairy cows were in L, M and H groups, respectively. Laminitis frequency, production and economic loss in H and M groups were greater than the L group. Milk production loss for H, M and L groups, were 0.98, 0.68 and 0.26 kg/cow/day. Also, economic loss was 791.4 US$ monthly, in dairy. This study showed that laminitis is important factor that affect production and incoming in Iranian dairy farms.