Biological aspects of Brevipalpus californicus (Banks) were studied on leaves of Navel orange at two temperature degrees 25 and 30°C and 70% R.H. The life cycle, generation time, and fecundity were affected by temperature degrees where the life cycle averaged 21.56 & 20.7 days and 17.11 & 15.6 days for females and males at temperature degrees 25 and 30°C, respectively. The generation time was 22.99 and 18.48 days at temperature degrees mentioned before. The fecundity of females was varied depended on temperature degrees where it was 16.71 eggs/ female at 25°C while it was 19.36 eggs/female at 30°C.