Abstract: Twelve local Saudi hens 33 weeks old at their peak egg production were used to determine the effect of an extra 2% supplemental feeding of L-arginine on luteinizing hormone secretion. Hens were randomly assigned into two treatment groups, they were fed either an extra amount of 2% arginine diet (treated) or not (control). Serial bleeding started 2 days after the start of the experimental feeding. One milliliter of blood were collected every 20 min starting at 9 h before the expected time for oviposition until 1 h after oviposition for the measurement of luteinizing hormone level. The results showed that feeding a 2% extra amounts of arginine to local Saudi hens significantly (p<0.05) increased mean LH level during the 9-6 h before the time of oviposition in arginine treated (2.8±0.33 ng mL-1) compared to control group (1.9±0.18 ng mL-1). Mean LH surge amplitude was also found to be higher in arginine treated compared to control group. The onset of the preovulatory LH surge was found to start earlier (p<0.05) in arginine compared to control group (260±30, 335±25 min before the time of oviposition, respectively). No significant differences were found between the two groups in the preovulatory LH surge duration. Further studies are needed to examine the effect of feeding an extra amounts of arginine on LH secretion and egg production in commercial breeds of hens.