Female New Zealand white rabbits were subjected to heparin treatment to induce osteoporosis and to observe the effects of calcitonin and tamoxifen treatments on the initiation of osteoporosis, The aim of this study is to investigate zinc-calcium interaction as well as the alterations of plasma biochemical parameters in these animals and, thus, to assist in clinical usage of these drugs. Thirty-two animals were divided into 4 groups and medicated for 8 weeks. The animals in group A were administered heparin (Liquemine) intraperitoneally at the dosage of 1,000 IU/kg/day. The animals in group B were injected the same amount of heparin as that of group A and, in addition, calcitonin at the dosage of 100 IU/kg/day. The animals in group C were medicated the same way as group B, but 2 mg/kg/day tamoxifen (Nolvadex) were orally added to their diet. The animals in last roup were the control, Studied variables, in addition to the biomechanical parameters various bones, a were all electrolytes such as sodium, potassium, chlorine, calcium and phosphorus levels in sera, creatinine, total protein, albumin, alkalene phosphalase, progesteron, estrogen, and globulin concentrations in plasma, and also zinc level in plasma. Heparin and heparin plus calcitonin treatment caused an increase and a decrease in the plasma calcium and zinc levels, respectively, with respect to the control (p < 0.05), whereas tamoxifen treatment in addition to heparin plus calcitonin did not alter the calcium level significantly, but still zinc revel was lower than the control (p < 0.05). Plasma mineral contents except phosphorus in 3 experimental groups decreased significantly with respect to the control. The estrogen and globulin levels in serum in all treated groups increased and these increases were statistically significant with respect to the control, whereas the serum albumin and alkalene phosphatase levels decreased significantly (P < 0.05). The results showed that some alterations in plasma biochemical parameters of heparin-induced osteoporotic animals are observed and some of these alterations are reversed by tamoxifen treatment of these animals.