The frequency of root-knot nematode (Meloidogyne spp.) occurrence on fig (Ficus carica L.) and weed plants was evaluated in different orchards in Rio Grande do Sul State, southern of Brazil. In the samples where root-knot was detected, species characterization was differentiated by electrophoresis using the isoenzymes esterase (Est) and malate-desydrogenase (Mdh). The nematode was detected in all fig plant samples and two Meloidogyne species were identified: M. incognita with the phenotypes (Est/Mdh) I1/N1, I2/N1, S1/N1 and or S2/N1 in all fig orchards and M. javanica (J2/N1) in only one orchard associated with M. incognita I1/N1. In the weeds collected under the canopy of fig trees, six host plants (Sida rhombifolia, Ipomoea nil, Commelina benghalensis, Asclepias curassavica, Solanum americanum and Ageratum conyzoides) of Meloidogyne spp. were identified. The frequency of Meloidogyne species in the weed samples was variable. The isoenzyme phenotypes corresponded to M. incognita (Est I1, I2, S1), M. javanica (Est J3 and J2), M. arenaria (Est A2), and M. ethiopica (Est E3). Among these weed plants, Sida rhombifolia was the species with major root gall presence in the weed hosts. The phenotypes I1, I2 and S1 of M. incognita and J2 of M. javanica, were also detected in fig trees, which is highly important to crop management.