Introduction. In general, chronic wounds are colonized by bacteria; however, when microorganisms start to multiply at higher levels, wounds can become infected, causing prolongation of the inflammatory phase and retardation of collagen synthesis and epithelialization. Objective. The objective of this study was to evaluate the presence of infection in venous ulcers after 12 weeks of treatment with autologous platelet-rich plasma (PRP) and determine global white blood cell counts. Materials and Methods. This case series study involved a sequential sample of 17 patients with venous ulcers treated with PRP for 12 weeks. Descriptive and inferential statistical analysis was performed using the McNemar test and χ² test. Results. At baseline, 10 patients (58.8%) had wound infection. During the sixth week of treatment with PRP, only 3 patients (17.6%) continued to exhibit wound infection. After 12 weeks of PRP treatment, only 1 patient (5.9%) continued to exhibit wound infection. McNemar and χ² tests used to assess the presence of infection in the intervention group produced a P value of .0039 for a comparison of baseline and week 6 and a P value of .0078 for a comparison of baseline and week 12. These results demonstrated significant differences from baseline at both 6 weeks and 12 weeks of treatment, with greater significance at 12 weeks. There was no relationship between global white blood cell count and the presence of infection. Conclusion. After intervention with PRP, 94% of patients experienced improvement concerning the infection of ulcers.