The aim of this study was to verify the occurrence of hemolysis after infusion of packed red blood cells (PRBCs) in 12 peripherally inserted central catheters (PICCs) with a proximal valve, according to size and infusion rate. This was an experimental in vitro study performed under laboratory-controlled conditions, and the sample was composed of 12 PICCs with proximal valves (3F and 4F catheter). Twelve type A+ aliquots from 10 PRBCs were analyzed preinfusion and postinfusion according to PICC size and infusion rate. Hemolysis markers, total hemoglobin (g/dL), hematocrit (%), free hemoglobin (g/dL), potassium (mmol/L), lactate dehydrogenase (U/L), and rate of hemolysis (%) were studied. Data were analyzed using analysis of variance and Bonferroni multiple comparison tests. After the infusions in 3F PICCs, an increase was seen in rate of hemolysis (P =.003) and free hemoglobin (P =.014), in addition to a reduction in total hemoglobin (P =.002), with significant influence of minimum and maximum flow rates on the rate of hemolysis. The study finding indicated that the smaller catheter size and the infusion rate influenced variations in some hemolysis markers, but the alterations observed in the hemolysis markers would not contraindicate the infusion of PRBCs by 3F and 4F PICCs with proximal valves.