Main inventories of cotton pests' parasitoids were made in Paraguay by B. Michel and P. Prudent (1987 to 1992). Collections of pests and their natural enemies have been done mainly during field visits of the national cotton program (PIEA) experimental plots through the country. The rearing of eggs, larvae and nymphs was done. From Alabama argillacea (cotton leaf worm, Noctuidae) and Chrysopid eggs, we obtained in Caacupe in 2001 the same parasitoid, Trichogramma pretiosum, identified by R. Zucchi (Esalq) in Brazil. Up to 4 individuals were obtained from 1 Chrysopid egg. From Pentatomidae eggs in Concepción emerged a Telenomus species (Scelionidae). From Aphis gossypii were recovered the very common Lysiphlebus testaceipes (Braconidae). We obtained two Braconids species from A. argillacea's caterpillars: Rhaconotus sp. and Bracon sp. This last species emerged from a cocoon fixed on the leave by a small peduncle. Copidosoma floridanum (Ashmead) (Encyrtidae) known as an Alabama's parasitoid was also observed on Pseudoplusia includens (soybean looper) in cotton. From an unidentified looper and external cocoons on the back of the caterpillar, emerged specimens of Glyptapanteles (Braconidae) in three different localities (Coronel Bogado, in 2002, Guayaybi and Caaguazu in 2004). Parasitoids of natural enemies are still not frequently observed. We've obtained a Pachyneuron sp. (Pteromalidae), emerging from a Coccinellid and Syrphid larvae, in Caacupe and Chord. An Eulophidae, Oomyzus sp. emerged from a Chrysopid nymph and a Prochiloneurus sp. (Chaldicidae) wad identified after rearing of a coccinellid larva (in Y'Jhovy). Hyperparasitoids were also identified: Syrphophagus aphidivorus (Pteromalidae), from A. gossypii (parasitoid probable of Lysiphlebus). Among the Chalcididae family, all the specimens got emerged from A. argillacea: Brachymeria annulata and B. subconica after rearing of the nymphs found in Concepción in 2001, Conura (ex Spilochalcis) fulvovariegata and Conur