The morphological ontogeny of Chamobates pusillus (Berlese, 1895) is described and illustrated. The larva of this species is unpigmented and without a gastronotal shield, whereas the shield is present in the nymphs and has 10 pairs of setae (d-, l-, h-series and p₁), while setae p₂, p₃ and of c-series are inserted on unsclerotized cuticle. In the juveniles, the length of most prodorsal setae and gastronotal seta c₃ increases during the ontogeny, whereas the length of most other gastronotal setae varies with stage. In the larva, these setae are of medium size, whereas in the protonymph and deutonymph the length of setae gradually decreases and remains short in the tritonymph. In the adult, most prodorsal setae remain long, but the notogastral setae are either lost (c₁, c₃ and d-series) or remain as alveoli (l- and h-series) or minute (c₂ and p-series) setae.