The high number of level I and II studies suggests that there is need for clarification and evaluation of the efficacy of several non-operative and operative treatment approaches for the chronic plantar fasciitis. However, to date there is no evidence in the literature that compares the new, promising technique of BTX-A injection into the gastroc-soleus complex to a sham (saline) injection and to the gold standard steroid injection at the plantar fascia insertion site. With the intended study, this gap is going to be closed. Objective evaluation of the BTX-A efficacy includes the randomized allocation of patients to the BTX-A, the steroid, or the saline group, the blinded comparison to the sham (saline) injection, and finally the MRI assessment at the beginning and at the end of the followup. With the evidence resulting from this study, patients can be superiorly counseled in the future with regard to efficacy of nonoperative treatment of plantar fasciitis.