Objective: Plantar fasciitis is one of the most common causes of heel pain. Conservative noninvasive lines of treatment are numerous, among which platelet-rich plasma (PRP) has recently been demonstrated to be helpful in managing plantar fasciitis. The aim of this study is to evaluate the platelet-rich plasma-ultrasound-guided injection in the treatment of plantar fasciitis through randomized double-blinded placebo-controlled study. Methods: Sixty-two adult plantar fasciitis patients were involved in the current study. They were randomly selected from the outpatient clinics of Physical Medicine, Rheumatology and Rehabilitation, Faculty of Medicine, Alexandria University. They were randomly divided to receive either saline (group 1) or PRP (group 2) injection under ultrasonography (US)-guidance. Assessment was done using visual analogue scale (VAS) for pain intensity at baseline and during 2 nd and 6 th weeks after injection. Functionally, foot function index (FFI) was used at baseline and during 6 th week after injection. Pain relief score (PRS) was measured during 2 nd and 6 th weeks after injection. Plantar fascia thickness was also measured sonographically by US at baseline and during 2 nd and 6 th weeks after injection. Results: There was no statistically significant difference between both groups as regards age, Body Mass Index and baseline US, VAS, and FFI scores. PRP (group 2) showed significant improvement in pain severity and physical limitations in patients with plantar fasciitis. It also showed significant improvement compared to saline group injection considering VAS, US, PRS, and FFI. Conclusion: The use of PRP injection for treatment of plantar fasciitis resulted in significant improvement in pain according to VAS, PRS, and FFI and a reduction in the thickness of the plantar fascia as measured by US, compared to the saline group.