Objective: Nanoparticles in the range of 10-100 nm in diameter are promising materials with interesting properties. These materials are in use in many fields, ranging from medical imaging, drug delivery and various industrial applications. Therefore, it needs to investigate their interaction with different types of cells in the body. Materials and Methods: SWCNTs (3-10nm in diameter and 10-20 µm in Length) were synthesized and calibrated in the department of Chemistry of Shiraz University. Raji, Jurkat and U937 cell lines, representative of B lymphocytes, T lymphocytes and myeloid cells, respectively, were treated in cell culture condition with different amounts of SWCNTs ranging from 0 to 200 µg/ml. After 24, 48 and 72 hours treatment, survival of these cell lines was assessed by MTT proliferation assay in triplicate experiments. Results: Different patterns of responses were observed from lymphoid and myeloid cells. U937 cells showed higher growth with low concentrations of SWCNTs 48 hours post-culture while higher concentrations resulted in down regulation of the growth, mostly at 72 hours of culture. Jurkat and Raji cells demonstrated an enhanced proliferation in the presence of low concentrations of SWCNTs in all tested time points however higher concentrations of these particles caused inhibition of cellular growth. Conclusion: The presence of SWNCTs can affect growth properties of the immune cells differently. Therefore, in clinical applications, precise concentrations of these materials should be selected to avoid cellular toxicity and possible side effects.