The aim of this study was to compare--clinically and ultrasonographically--the therapeutic effects of physical therapy modalities (hot pack, ultrasound therapy, and friction massage), local corticosteroid injection, and extracorporeal shock wave treatment (ESWT) in lateral epicondylitis (LE). Fifty-nine elbows of 59 patients with LE were randomized into three treatment groups receiving either physical therapy, a single corticosteroid injection, or ESWT. Visual analogue scale (VAS) was used to assess pain intensity, Jamar hydraulic dynamometer for grip strength, finger dynamometer for pinch strength (before treatment, on the first, third, and sixth months of treatment). All subjects were also evaluated with ultrasonography before and 6 months after treatment. In all groups, VAS scores of the patients were found to decrease significantly on the first, third, and sixth months of treatment. With respect to grip strength evaluations, the increase after treatment was significant only on the first month in group II; on the first and third months in group I; and on the first, third, and sixth months of treatment in group III. Pinch strength and ultrasonographical findings did not change during follow-up in any group. We imply that physical therapy modalities, corticosteroid injection, and ESWT have favorable effects on pain and grip strength in the early period of LE treatment. The increase in grip strength lasts longer with ESWT. On the other hand, ultrasonographic findings do not change in the first six months of these treatment methods.