The oxygen binding capacity of human erythrocytes in selected solutions was studied in vitro. Three treatment groups were used in the study: 0.08% iota-carrageenan solution, dextran 70, and normal saline solution (NSS). The different treatment groups were oxygenated. The percent oxygen saturation and oxygen partial pressure were determined by blood gas analysis, and oxyhemoglobin absorbance was measured using spectrophotometry. Analysis of variance (ANOVA) and Tukey's HSD Test were used to analyze the data. There were significant differences (p<0.05) observed in the percent oxygen saturations and oxygen partial pressures among the three treatment groups, with NSS having the highest values (97.65+/-0.385% and 160.18+/-152.567 mmHg, respectively) followed by dextran 70 (95.38+/-1.093% and 142.68+/-73.967 mmHg, respectively) then iota-carrageenan (89.42+/-4.327% and 94.02+/-17.912 mmHg, respectively). However, there were no significant differences observed in the absorbance values of oxyhemoglobin among the three set-ups. It was concluded that the oxygen binding capacity of erythrocytes in iota-carrageenan solution is significantly lower than that in dextran 70 and NSS.