Objective: To determine the effect of Growing up milk (GUM) fortified n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) to improve nutrition status and upper respiratory infection in children during 12 weeks. Subject and Method: A double-blind, placebo-control trial was done in 1-3 year children. Total of 130 children were selected and randomly divided into 2 groups as following: 65 children in intervention group and 65 children in control group. The individual in both groups was given 3 servings of milk per day (210 ml milk! serving) by teachers in the kindergarten during 12 weeks. Intervention group was served GUM milk fortified with 15,6mg n-3 LCPUFA /100ml, and control group was served milk with l.3mg n-3 LCPUFA/100ml. Nutrition status (body weight and height, percentage of malnutrition), serum Vitamin D, DHA and EPA concentration were assessed before and after intervention. Upper respiratory infection status of all subjects was monitored during whole time of intervention. Result: Mean of body weight in both groups increased 0.7 kg, higher in interventions (0.9kg) compared with controls (0.5kg), p0.05. Prevalence of Vitamin D deficiency decreased from 67 percent in baseline survey to 6 percent at the end of study (p0.001). Intervention group showed significantly lower incidence of upper respiratory infection symptoms, fewer numbers of infectious episodes, and shorter duration of illness compared with control group. Conclusion: GUM milk fortified n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) has positive effect to improve nutrition status and upper respiratory infection in children aged 1-3 years.