We studied the reproductive ecology of a population of the lacertid lizard Lacerta monticola at a lowland location in A Coruña (NW Spain) from 1997 to 2002. The timing of the reproductive cycle was examined based on mark-recapture records of individual lizards in the eld. The characteristics of the eggs and hatchlings were obtained from clutches laid in the laboratory by pregnant females that were temporarily removed from the study area. Our results indicate that mating took place between late March and July. The smallest female with signs of sexual maturity had a snoutvent length (SVL) of 52.4 mm and the smallest male was 50.7 mm. Sexual maturity was attained at the age of 2 years by 41% of the individuals, while the remaining 59% of the lizards matured at the age of 3 years. The laying period occurred between June and the beginning of August considering all years. About 61% of the reproductive females produced a single clutch annually, while 39% of the females produced two clutches per year. Females that produced two clutches were generally larger (average SVL D 70.9 mm) than those that laid a single annual clutch (average SVL D 62.6 mm). The mean clutch size was 6.4 eggs (range 4-9). Both clutch size and clutch mass increased signi cantly with female SVL. The mean egg mass in a clutch decreased signi cantly with clutch size. Hatching occurred between August and September. Hatching success in the laboratory was 71.7%. The mean SVL was higher in female hatchlings than in males.