A deep understanding of vector biology enables us to discover mechanisms of disease transmission and to design modern and effective strategies for vector control. Although Cx. (Cx.) univittatus is one of the main disease vectors in Saudi Arabia and worldwide, little information on its biology and population dynamics are available. Herein we evaluated many biological and reproductive attributes of Cx. univittatus mosquito from Saudi Arabia, under semi-field conditions. We found that female Cx. univittatus spent half of its longevity in digestion of blood meal and oviposition. To that end, a mortality rate of 44.5 % was recorded due to feeding and oviposition. Survival rates of different life stages of Cx. univittatus mosquito were assessed, too. The fecundity of female Cx. univittatus was estimated 157.4 eggs/ female. Fertility was evaluated 65%. 35% of eggs failed to hatch. Only 41 % of the hatched larvae developed to pupae and 43 % of pupae developed to adults. Chi-square test indicated that sex ratio is biased in favor of female to compensate the loss in generations. Developmental period from egg to adult was 20 days (2.1 for egg, 15.3 for larva, 1.5 for pupa). These findings support the conclusion that the environmental factors and habitat conditions have major impact on the vector biological attributes and in turn, on the vector competence for a disease.