We investigated the effect of carbon black nanomaterial (NM CB) on membranes of blood cells and of giant unilamelar phospholipid vesicles (GUV). The aim of the study was to determine whether NM CB effects the shape of blood cells and GUVs. The samples of isolated blood cells, full human blood and GUVs were incubated with different concentrations of NM CB. We observed the shape changes of erythrocytes due to the presence of NM CB in the samples; the abundance of discocytes, echinocytes and stomatocytes in the treated samples was changed with respect to control samples. NM CB also affected the adhesion of erythrocytes to agglomerates of nanomaterial. Tubular protrusions on platelet membrane occurred after 3 and 24 hours both in the samples incubated with NM CB and in the control ones; no differences were found in activation of platelets in the respective samples. However, statistically significant differences were observed in the average number of leukocytes as well as of eosinophils, basophils and monocytes with respect to control samples. Incubation of GUVs with NM CB caused a considerable and statistically significant decrease in their number while the contours of the remaining GUVs exhibited on average higher eccentricity than the control ones. It was concluded that the presence of NM CB in the samples with blood cells did not cause hemolysis. We did not detect hemolysis or changes in cell membranes due to the presence of NM CB that could impair the function of blood cells. We observed disintegration of GUV membranes which was, similarly to the erythrocyte shape change, interpreted as a secondary osmotic effect.