Objectives: Health-related fitness is a good predictor of health status of children and adults. Less is known about relationships of health-related fitness components between parents and children. Methods: Our study involved 58 children (30 girls and 28 boys, mean age = 7.97) and 58 parents (33 mothers, mean age = 39.32, and 25 fathers, mean age = 38.73) who were voluntarily enrolled in the program in 3 selected primary schools in the city of Poznan, Poland. Physical fitness was measured using the Eurofit test battery. Assessment of body composition was performed by measuring the bioimpedance. Results: Positive relationships were found among the levels of strength of abdominal muscle, flexibility of parents, and the slenderness of children. Slimmer parents also had more physically active children. Body composition parameters also were related to physical activity. More relationships were found between children and parents of the same sex. Conclusion: Data support the hypothesis that health-related risk factors are linked between parents and children and that sex plays an important role in these relationships. Our findings reinforce the need to develop health promotion programs that include children and their parents.