Odon. of streams, small rivers and ponds were sampled in the Yungas cloud forest of NW Argentina, and presence / absence information of spp. from samples and from examination of collections was recorded in a spatial-relational data base. Alpha, beta, and gamma diversity and total species richness expected for the area were estimated. Similarity in composition of odon. communities from lotic and lentic environments were analyzed according to latitudinal and altitudinal gradients, using multivariate cluster analysis. Assemblages from NW Argentina were compared to those from equivalent sites in SE Peru. Odon. species diversity was found to follow both a latitudinal (decreasing from N to S) as an altitudinal gradient (decreasing from low to high elevations). Based on IUCN (2001) criteria, the conservation status of the odon. spp. endemic to the Yungas cloud forest was assessed at a global scale; 6 spp. were assessed as of Least Concern and 2 as Near Threatened.