Introduction: We aim to examine the role of Platelet to lymphocyte ratio (PLR) and Platelet to Lymphocyte and monocyte ratio (PLT/LY+MO) values in Respiratory Syncytial Virus (RSV) infection. Methodology: Complete blood counts and RSV Antigen test results of 76 patients, between the age of 0-12 were investigated retrospectively. PLR values are calculated using Platelet Count / Lymphocyte Count formula, whereas PLMR values are calculated using Platelet Count / Lymphocyte Count + Monocyte Count. Results: Out of 76, 32 patients were diagnosed as RSV infected. Lymphocyte and monocyte percentage and platelet count were significantly higher in RSV positive group. Monocyte percentage in lower respiratory tract RSV infection was significantly lower compared to upper respiratory tract RSV infection. Conclusions: Our study revealed that these blood parameters may be an important clue for the clinician for RSV infection and also play a role as a guide before advanced techniques.