The aim of this cross-sectional study was to assess the influence of simvastatin treatment in children with familial hypercholesterolemia (FH) on parameters of cellular immunity. Twenty-six children with FH were included, of which thirteen were treated with 10 mg simvastatin for at least 26 weeks, and thirteen were age- and sex-matched with a low-cholesterol diet only. Total WBC count and lipid profile were measured. Flow cytometry was used to identify lymphocyte subsets and determine the expression of adhesion molecules (AM) and toll-like receptors (TLRs) on leukocytes. No differences were found in the basic values of peripheral blood count and subpopulations of lymphocytes between groups. The percentage of granulocytes with the expression of AM was higher in those treated with statins. The TLR-2 expression on granulocytes and monocytes showed higher values, whereas the TLR-4 expression was lower on lymphocytes and granulocytes in simvastatin-treated children. Treatment with simvastatin in children with FH is not associated with alterations in the amounts of granulocytes and monocytes. There is no association between statin treatment and the pattern of peripheral blood lymphocyte subpopulations. The role of AM and TLRs needs further investigation, given the effect of statins on the innate immunity may be important for their efficacy and safety during growth.