Object: Analysis of serum tumor markers CA-125, CEA, AFP, & ß-HCG in patientswith ovarian malignant tumors and correlation of their serum levels with histological types. StudyDesign: Institution based descriptive and prospective study. Place & Duration: Department ofPathology, Liaquat University of Medical & Health Sciences, Jamshoro from January 2009 toJune 2011. Material & Methods: One hundred cases, diagnosed as ovarian malignant tumor onH&E staining were selected for study & measurement of serum CA-125, CEA, AFP, & ß-HCGpreoperatively and postoperatively in each case. Results: Out of 100 ovarian cancers diagnosedon H&E stain 33 were serous cystadenocarcinoma, 29 mucinous adenocarcinoma, 19 germ celltumors and 15 sex-cord stromal tumors, 1 endometroid carcinoma, 1 brenner tumor, 1 clear cellcarcinoma and 1 case of NHL. Increased level of CA-125 was seen preoperatively in 33/33 casesof serous cystadenocarcinoma and 24/29 cases of mucinous adenocarcinoma. Surprisinglyincreased levels were also seen in 10/19 germ cell tumor and 8/15 in sex-cord stromal tumors.CEA is raised in mucinous tumors. AFP & ß-HCG were raised in germ cell tumors & sex cordstromaltumors. Serum tumor marker levels were declined following appropriate therapy of thetumors. Conclusions: Serum tumor markers are useful and important for the detection of ovariantumors. They may also help in assessment of response to specific treatment, prognosis & followup of patient.