The effect of undernutrition on gene expression of progesterone and oestrogen receptors (PGR and ESR1), and insulin-like growth factors 1 and 2 (IGF1 and IGF2) in the uterus and oviducts of ewes on day 5 after oestrus was investigated. The effect of the side of the uterus/oviduct regarding the ovary bearing a corpus luteum (CL) (ipsi vs. contralateral) was also analyzed. Fourteen oestrous synchronized ewes were fed either 1.5 (C, n=7) or 0.5 (L, n=7) times their maintenance requirements from the onset of the hormonal treatment (day -14), till slaughter on day 5 post-oestrus. Oviducts and samples of uterus were collected and their gene expression studied by real time RT-PCR. Undernourished ewes had greater PGR expression in the oviduct than control ewes, but lower expression of IGF1 in uterus and of IGF2 in oviducts. The ipsilateral oviduct presented lower expression of PGR, ESR1 and IGF2 mRNA than the contralateral one, but this did not occur in the uterus. In conclusion, there is an effect of undernutrition on gene expression that is transcript and organ dependent (uterus/oviduct). This work reports for the first time that growth factors and sex steroid receptor expression on day 5 after oestrus vary depending on the side of the CL-bearing ovary and the region of the reproductive tract.