Objective: To evaluate the role of serum creatine kinase (CK) and progesterone (p) in the prediction of ectopic pregnancy (E.P). Patients and methods: A prospective study was carried out on 60 pregnant women of comparable gestational age and they were divided into 3 groups: Group A: 20 patients with confirmed E.P. Group B: 20 patients with missed or spontaneous miscarriage. Group C: 20 women with normal intrauterine pregnancy (IUP). The following laboratory measurements were performed for the studied groups: 1- Test for serum CK level for all groups. 2- Test for serum progesterone for all groups. 3- Histopathological study to determine the depth of invasion of the trophoblast to the muscular layer of fallopian tube for group A. Results: 1- The serum CK level was significantly higher in group A than in group B and C and was significantly higher in ruptured than in unruptured and in isthmic compared to ampullary EP. 2- The serum progesterone level was significantly lower in group A and B than in group C, but there was no significant difference between group A and B. 3- The serum progesterone level was significantly higher in ruptured than in unruptured EP. 4- There was significant positive correlation between serum CK and progesterone level in group A. Conclusion: 1- An increase in serum CK levels probably antedates tubal rupture and could help in discriminating ruptured from unruptured EP. 2- Serum progesterone discriminates EP from normal IUP but it does not differentiate it from miscarriage. 3- The combination of both serum CK and progesterone in suspected EP has a higher differential accuracy than either analysis alone