A malaria serologic survey was carried out in first grade school children from Marabá, PA. Immunofluorescence (IF) test was used for the detection of IgG and IgM antibodies to P. falciparum and to P. gallinaceum. Also, hemagglutination (HAg) test with P. gallinaceum infected erythrocytes was employed. The IF-IgG test with P. falciparum was positive in 6.94% of the 389 individuals studied, and the IF-IgG test with P. gallinaceum in 11.56%. Agreement between both tests 'was observed in 88.68% of sera. A total 14.91% reactive cases were seen by any of the two tests. The IF test using P. gallinaceum as antigen showed higher positivity than P. falciparum probably due to the predominance of T. vivax infection in that area. A statistically significant difference (P < 0.05) was observed for IF-IgG test with P. falciparum antigen between the age group A (6 to 10 years) and group B (11 to 16 years). However, this was not seen when P. gallinaceum antigen was applied. The positivity obtained in IF-IgM and HAg tests were respectively 2.83% and 1.80%, with no significant differences between the referred age groups (P > 0.05).