Bothrops insularis is a snake from Queimada Grande Island, which is an island located about 20 miles away from the southeastern coast of Brazil. Compared to other Brazilian species of Bothrops, the toxinology of B. insularis is still poorly understood. Its C-type lectin is involved in several biological processes including anticoagulant and platelet-modulating activities. We purified the C-type lectin (BiLec) from Bothrops insularis venom and investigated its effect in the isolated kidney. BiLec was purified after two chromatographic steps; firstly, the whole venom was submitted to an HPLC molecular exclusion chromatography followed by a second purification through affinity chromatography. B. insularis lectin (BiLec) was studied as to its effect on the renal function of isolated perfused rat kidneys with the use of six Wistar rats. The concentration of 10μg/mL increased perfusion pressure (PP; control 60 =108.27±4.9; BiLec 60 =112.9±5.4mmHg; *p<0.05) and renal vascular resistance (RVR; control 60 =5.38±0.51; BiLec 60 =6.01±0.57 mmHg; *p<0.05). The urinary flow reduced significantly at 90 and 120min of perfusion (UF; control 120 =0.160±0.020; BiLec 120 =0.082±0.008mLg −1 min −1 ; *p<0.05). Glomerular filtration rate (GFR; control 120 =0.697±0.084; BiLec 120 =0.394±0.063 mLg −1 min −1 ; *p<0.05) diminished only at 120min. BiLec did not change the percentage of sodium (TNa + ), potassium (TK + ) and chloride tubular transport (TCl − ). The histological alterations probably reflected direct injury on glomerular and tubular renal cells, as demonstrated by the rise in permeability of glomerular endothelial cells, revealed by the presence of a proteinaceous material in the Bowman space. We postulate that the C-type lectin B. insularis promoted its effects probably through interactions with endothelial cells or through the release of other mediators by tubular, mesangial and endothelial cells.