Laboratory studies were conducted to assess the effect of soil moisture and temperature on the development of the preimaginal stages of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). The number of days required for the immature flies to complete their development and reach the adult stage (development time) were studied at five temperatures (15, 20, 25, 30, and 35°C) and under five soil moisture regimes (-2.14 Mpa [mega Pascal] [1% (wt:wt)], -0.5 MPa [5.0% (wt:wt)], -0.47 MPa [9.0% (wt:wt)], -0.28 MPa [13.0% (wt:wt)], and -0.23 MPa [17.0% (wt:wt)]). A parametric survival model describing the effect of linear and quadratic combinations of temperature and soil moisture and their interaction on the probability of completing the development over the experimental period was used. The lognormal parametric survival model was significant for C. capitata preimaginal development, with DT50 (the development time for 50% of the preimaginal C. capitata to reach the adult stage) ranging from 12.8 to 32.4 d. The highest percentages of adult emergence at 30 d were obtained at 24.8°C and intermediate soil moistures of 5.0 to 13.0% wt:wt. The average development time of the medfly preimaginals reaching the adult stage was inversely related to temperature and ranged from 7.4 to 26.1 d. This model could allow the monitoring of medfly preimaginal natural mortality in the soil, the prediction of adult emergence under field conditions, and therefore, the identification of suitable application times in the medfly lifecycle to achieve the maximum degree of adult and preimaginal control.