Background: The government has made efforts to improve children's growth and development through programs in primary health care, but the reduction in stunting and child development delay has not been as expected. Implementation of these programs needs support from all stakeholders, including health cadres and also the family as the main caregiver of a child. Objective: analyzed the effect of family assistance on the growth and development of the under two years old children. Method: this was a quasi-experimental study with a pre-post control group design. Subjects were 63 stunted under two years old children with developmental delay. The intervention group of 32 children was assisted by trained health cadres, namely the Kader PendampingKeluargaKawalBaduta[KP-KKB] for 4 months, while 31 control group children were not accompanied. Results: The implementation of the KP-KKB strategy model shows: mean different changes in subjects and control of nutritional status HAZ-score of 0.09 [Wilcoxon]; WHZ-Score of 0.2; and WAZ-Score of 0.21 [Paired t-test] in the intervention group. Changes in the mean status of motor development are 3.6; and social personal 0.88 [paired t-test] in the intervention group. The results of the paired statistical test of changes in nutritional status and the initial and final development of each group showed significant changes with a value of p <0.05. Conclusion: the KP-KKB intervention strategy model showed changes in nutritional status and improved development compared to the control group.