The present study aimed to compare short-term clinical outcomes between intraarticular platelet-rich plasma (PRP) and hyaluronic acid (HA) treatments in early-stage gonarthrosis patients. Data of gonarthrosis patients, who were stage 1 or stage 2 according to Kellgren–Lawrence classification and underwent intraarticular PRP or HA treatment, were obtained retrospectively. The patients received treatment for three times at one-week intervals (intraarticular PRP or HA). They were evaluated using the Knee Society’s Knee Scoring System (KSS) and the visual analog scale (VAS) scoring system before treatment and at the second and sixth months of treatment. The study included 132 patients (mean age, 55.06 ± 8.41 years). Sixty-three patients (86 knees) were in the HA group and 69 patients (89 knees) were in the PRP group. Changes in KSS and VAS scores over time and the differences between the treatment groups in terms of changes in KSS and VAS scores over time were significant. In conclusion, PRP appears to be an appropriate option for intraarticular treatment in patients with early-stage knee osteoarthritis.