Several species of leishmania and three methods of cultivation: monophasic, biphasic and co-cultivation were used in a compared study bearing on the intensive production of leishmania. In addition by applying, a new in vivo model, comprising an injection of sarcomatous cells and promastigotes into BALB/c mice and also an extraction on a discontinuous gradient (Radioselectan 60%), it was possible to obtain highly purified isolates of amastigote forms. The use of two antigens: promastigotes and amastigotes, is to be recommended for the serological diagnosis, by indirect immunofluorescence, of kala-azar. The new in vivo model merits further consideration for research concerning new molecules active against leishmania.