This study was designed to evaluate the effects of testosterone propionate (TP) on hatchability, chick measurements and some plasma metabolites in Dokki- 4 strain of chickens during embryogenesis stage. A total of 350 fertile eggs (45-55 g. in average) were individually weighed and incubated .At the 5th day of incubation, eggs were divided into 3 experimental groups as follow; control(C) non-injected groups ,while the other groups T1 and T2 eggs were injected in albumin with 25 and 100µg TP solvated in 50µl plant oil.  Results showed that hatchability % was significantly decreased in-ovo injected groups by 1214%than control groups, while embryonic mortality rate was increased by in-ovo injection with TP. Chick weight, total protein, albumin, calcium and phosphorus levels were significantly increased in TP injection than control .Also, male chicks % based on the visual examination was increased by TP in –ovo injection than control.   In conclusion: in-ovo injection of TP at the 5th day of incubation with 25 and 100µg TP/50µl plant oil had decreased the hatchability %, but increased embryonic mortality, some plasma constituents, male% ,chick weight and chick length in Dokki-4 strain of chickens.