A total of 54 miscarriage patients were divided into 3 groups. GI: 10 toxoplasmosis patients with +ve IgM-ELISA; GII: 24 toxoplasmosis patients with +ve IgG-ELISA, and GIII: 20 non-toxoplasmosis cross-matched females as a control. All groups were subjected to IgG-avidity ELISA & IgG-avidity immunoblotting. Avidity Indices (AI) by ELISA ranged from 22.6% to 73.3% in GI and from 9.6%-75.6% in GII. AI were high (>40%) in 3 (30%) patients in G I and in 8 (33.3%) patients in G II. Sera of GI recognized the 20, 28, 32, 60, 93 & 100 Kda bands with 55% reduction in the 38 and 60 Kda bands after treatment with 6 M urea solutions. Sera of GII recognized the 20, 28, 32, 38, 45, 95-97 & 106 Kda bands. There was 12.5%, 16.6% & 16.7% reduction in the 20, 32, & 106 Kda bands, respectively, after urea. The 38 & 60 Kda bands were identified as good diagnostic markers for the recent toxoplasmosis infection (GI). The 20, 32 & 106 Kda bands were good markers of high avidity antibodies during the chronic toxoplasmosis (GII).