Some details on the biology, behavior and laboratory mass rearing of Anastrepha obliqua are offered. Information on larvaI diets and oviposition substrates are discussed. Eggs of A. obliqua are, very succeptible to dehydratation and they collapse just few minutes after oviposition, if substrate for oviposition is not near 100% R.H. When using fruits as oviposition substrate, smallerfruit species, Spanish plums (Spondias spp.) offer higher yields. Bigger fruits (mango) loose large amounts of water and it accumulates in the sand substrate drowning mature larvae. After analyzing the biological cycle, the weaker part seems to be the 20 minute period in which mature larvae abandon the fallen fruit substrate and crawl few a centimeters on the floor seeking for an appropiate place for ovipositing. In this period large amounts of predators easily diminish larval population. Once pupation takes place, adult forms hatch in small groups, after eleven days, when atmosferic relativehumidity reaches 70%. Another observations are also included.