The aim of this study was to evaluate if pulsed electromagnetic field therapy (PEMF) has additional effect on the classical physical treatment of knee osteoarthritis (OA) composed of hot pack, therapeutic ultrasound, and terminal isometric exercises. Forty patients (29 women and 11 men), ages 44 to 78 (mean age was 61.3 ± 7.8 years) were included in our study. Patients with knee osteoarthritis [Kellgren–Lawrence criteria grade 2 and above and an average pain intensity of 40 or more on a 100-mm visual analog scale (VAS)] recruited from outpatient physical medicine and rehabilitation clinic were randomly assigned to receive PEMF or sham PEMF treatment in addition to their physical therapy. Both the PEMF and sham PEMF treatments being evaluated were 55 min/session, five sessions per week for 2 weeks. Each session comprise 20-min hot pack, 5-min therapeutic ultrasound, and 30-min PEMF or sham PEMF treatment applied to the knee of the patients. Patients were evaluated by the Western Ontario and McMasters Universities Osteoarthritis (WOMAC) Index and VAS at the baseline and at the end of treatment. Both PEMF and sham PEMF treatment groups showed statistically significant improvement in WOMAC pain and functional scores at the end of treatment (p < 0.001 in both groups). There were no statistically significant differences between groups in WOMAC pain, stiffness, and physical function scores after treatment (p = 0.906, p = 0.855, p = 0.809, respectively). There was neither difference in concomitant used acetaminophen dose in both groups (p = 0.289). The results of this study show that PEMF does not have additional effect on the classical physical treatment in reducing symptoms of knee OA.