Some of hypothyroidism impact are infertility, stillbirth, lactation disturbance, and menstrual abnormalities. hypothyroidism in women cause ovulation dysfunction and oligomenorrhea but can alsocause ovulation and conseption problem. This study aimed to describe the efect of hypothyroid on estrous cycle and ovary histologic structure on sprague dawley rat with propylthiouracil induction. This is an experimental study the samples were five hypothyroid sprague dawley rats and six control rats. Estrous cycle data were collected from vaginal smear slides. Ovary histologic structure data were analyse from ovary histologic slides. variables examined were free T4, numbers of ovary follicles,estrous cycles and ovary histologic structure. Quantitative data were analyzed statistically using independent t-test. Level free T4 from hypothyroid sprague dawley rats were 4.2 ± 0.6pmol/L and control were 8.2 ± 1.6pmol/L, p value 0,001. Estrous cycle of two groups were different in diestrous cycle. Percent amount of follicles primer were 19.6±5.9% and control 20.1±10.1%, p value 0.92, sekunder 27.8±10.1% and control 29.1±10.9% p value 0.84, tertier 2.8±2.8% and control 6.1±5.4%, p value 0.24, atretic 28.4±6.2% and control 29.5±10.0% p value 0.83, corpus luteal 20.0±17.1% and control 15.2±5.3% p value 0.52. Qualitative data of ovary histologic structure were not different. Estrous cycles of two groups sprague dawley rats were different in diestrous cycle. Damaged of ovary histologic structure appeared in two groups rats. Percent amount of follicles primer, secunder, tertier and corpus luteal two groups rats were not significantly different.Keywords: Hypothyroid, follicle ovarium, estrous cycle.