Differential diagnosis between physiologic bow legs and nonphysiologic bow legs is difficult and still not fixed in diagnosis, especially under 5 years old age. Recently the problem exist in differential diagnosis and treatment method of rickets because of non-specific laberatory finding in rickets. Metaphyseal-Diaphyseal angle in distal femur, Diaphyseal-Diaphyseal angle between femur and tibia, and Metaphyseal-Diaphyseal angle in proximal and distal tibia, and Metaphyseal-Metaphyseal angle in tibia are measured and compared for 30 bow legs children. And divided into rickets group and physiologic bow legs group by clinical and laboratory findings. The results are as following 1. Mean age was 1.91 years old at initail examination, 2.08 years old in rickets group, 1.73 years old in phisiologic bow legs group. 2. Diaphyseal-Disphyseal angle between femur and tibia was 18.12 ±6.80 in rickets group. And 10.17±5.36 in phisiologic bow legs group. Metaphyseal-Diaphyseal angle in distal femur was 10.88±3.62 in rickets group. And 8.42±4.42 in physiologic bow group. 3. Metaphyseal-Diaphyseal angle in proximal tibia was 11.50±2.56 in rickets group. And 7.17±2.01 in phisiologic bow legs group. It's angle in distal tibia was 10.50±3.86 in the former and 9.50 ±3.09 in the later group. Metaphyseal-Metaphyseal angle in tibia was 20.68±3.91 in rickets group and 16.78±4.11 in phisiologic bow legs group. According to the above mentioned results. Metaphyseal-Metaphyseal angle and Metaphyseal- Diaphyseal angle in tibia are comparable to gross appearance of bow legs deformed children rater than Diaphyseal-Diaphysealangle between femur and tibia, and Metaphyseal-Diaphyseal angle in distal femur. All values are high in rchekts, statistically. Therfore measurement of above mentioned angle in simple X-ray is valuable in differential diagnosis between phisiologic bow legs and Rickets.