Bone composition and bio-availability of calcium (289mg %) from egg shell, Oyster shell and vegetable mixture with variable quality of proteins (10g %) was studied after 4 weeks of experimental feeding in 25 young albino rats weighing 60.9–63.3g. Fresh femoral and tibial weight, length, moisture, dry weight and fat-free dry weight were observed highest in egg protein Gr IV and lowest in vegetable protein Gr V as compared to control Gr I. The egg shell was also found to be better than Oyster shell in this respect. In contrast, both femoral and tibial fat levels were high in Gr V (12.61 and 15.23g %) and very low in Gr IV (3.50 and 4.50g %) as compared to Gr I (8.29 and 9.45g %) respectively. Femoral and tibial (fresh weight basis) calcium and phosphorus levels were highest in Gr IV (8.82 and 2.29g %, 9.71 & 2.89g % respectively), higher in Gr IV and high in casein plus Oyster shell Gr II when compared with Gr I or casein plus egg shell Gr III. Femoral iron content was highest in Gr V (9.39mg %) and tibial iron in Gr II (8.46mg %). Further the calcium and phosphorus levels were lower and iron content was higher in femur than in tibia. Femoral (fat-free dry bone) ash weight was highest in Gr N (50.23g %) and lower in other groups as compared to Gr I (49.85g %), while femoral ash weight in Gr II (49.34g %) was higher than in Gr III (48.18g %). Femoral calcium, phosphorus and iron levels were greater in Gr V compared to all other groups. Iron level was moderately good in casein plus Oyster shell Gr II. The tibial (fat-free dry bone) ash and calcium levels were greater in Gr V (52.74 and 17.91g %) respectively, phosphorus in Gr IV (5.26g %) & iron in Gr II (16.98mg %). Casein plus Oyster shell showed better results than casein plus egg shell group in respect of tibial ash and mineral contents. It is concluded that the calcium bioavailability was the best in egg protein as compared to casein and vegetable proteins. There was no difference in available calcium from Oyster shell and egg shell as compared to salt mixture used in the experiment.