1- Serum LH level was measured in three groups of individuals, by Immunoradiometric assay (IRMA). Group one consisted of (8) premenopausal women suffering from benign serous ovarian tumor. Group two consisted of (4) premenopausal women suffering from malignant serous ovarian tumor. Group three consisted of (10) control premenopausal women.2- The presence of LH was investigated in two groups of benign serous ovarian tumors and one group of malignant serous ovarian tumors. The results obtained indicate a higher incidence of LH in the malignant tumors than in the benign tumors.3-The characteristics of the binding of 125I-anti LH antibody with LH in pre-and postmenopausal patients with benign and malignant serous ovarian tumors homogenate were investigated. Different factors affecting this binding was extensively studied such as, pH, time, temperature, salts, the concentration of 125I-anti LH antibody and the concentration of LH.4- The time-course of 125I-anti LH antibody with LH in pre-and postmenopausal patients with benign and malignant serous ovarian tumors homogenate was studied at five different temperatures. The obtained data have obeyed pseudo-first order Kinetics for the association of 125I-anti LH antibody with LH.5- The kinetic parameters K+1, K-1, Ka, and Kd of the binding of 125I-anti LH antibody with LH in pre-and postmenopausal patients with benign and malignant serous ovarian tumors were determined at five different temperatures.6- The thermodynamic of the 125I-anti LH antibody binding with LH in pre-and postmenopausal patients with benign and malignant serous ovarian tumors was studied by using Van't Hoff and Arrhenius equations. From these equations the thermodynamic parameters of the standard state ( ) and the transition state ( and also Ea) were determined.7- The (125I-anti LH antibody/LH) complex was isolated from the unbound 125I-anti LH antibody by gel filtration technique in pre-and postmenopausal patients with benign and malignant serous ovarian tumors. The absorption spectra of the isolated complex and the unbound 125I-anti LH antibody were studied.8- Spectroscopic studies in the U.V region were carried out on the unbound 125I-anti LH antibody and (125I-anti LH antibody/LH) complex in premenopausal patients with malignant serous ovarian tumors. The effect of pH and polarity on the spectra and observation of the thermal stability of (125I-anti LH antibody/LH) complex were studied.