"This research was done to explain about blood profile of mudskipper (Periophthalmodon schlosseri) by calculation erythrocytes count, hemoglobin, haematocrit, calculation of index erythrocyte which consist of calculation of mean corpuscular volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC), also calculation leukocytes count. Sampling used endangered animal catching method with line transect method. This research was used P. schlosseri with length about 25,4 – 28. Samples were taken from Barito River estuary at intertidal zone of Bahagia River, Tanipah village, Aluh-Aluh South Kalimantan. Blood test of P. shlosseri based on Hematology method. Results showed that erythrocyte count was 3,36±0,1x106 cell/μL; hemoglobin value 12,38±0,56 gr%; hematocrit 41,53±0,60 %; MCV 123,78±3,94 μm3; MCH 36,88±1,82 pg/cell; MCHC 29,80±1,18 g/dL and leukocyte count was 222,62±5,09 cell/μL. Blood profile of P. schlosseri from Barito River Estuary South Kalimantan is the result of environment adaptation and amphibious behavior (air-breathing)."