During the last several decades, the prevalence of childhood overweight and obesity achieved an alarming rate. Unfortunately, it also affects children in the preschool age. In this review, special emphases are made on determinants and risk factors for obesity development in early age, effectiveness of preventive strategies in preschool children and outcome measurements of intervention programme in preschool children. It is concluded that prevention of overweight and obesity in younger children is not an easy task but it could be even more rewarding than in the older age group. All the efforts should be made to stop this adverse public health problem from expanding.