To determine the possible predictive value of certain acute phase reactants CRP and ESR as well as radiologic parameters on the degree of impaction in ureteral stones. A total of 80 adult patients with a single opaque proximal ureteral stone were evaluated. A non-contrast CT was performed in all cases and all possible radiologic predictive parameters calculated. Additionally, to outline the degree of impaction at the stone site, two serum acute phase reactants namely CRP and ESR levels were also assessed. Patients were divided into two groups as follows; Group 1 (n:42) patients with normal CRP levels and Group 2 (n:38) patients with elevated levels of CRP. The data obtained in the subgroups were first comparatively evaluated with radiological parameters and the possible correlation between CRP values and these parameters was well evaluated. While the serum CRP levels were normal in 42 cases, they were elevated in 38 cases. Evaluation of the data from CRP subgroups and radiologic parameters showed that elevated levels of serum CRP were closely related with mean values of ureteral wall thickness (UWT) as well as mean level of hydronephrosis with a statistically significant difference. Additionally, a correlation analysis between serum CRP levels and all other parameters mentioned above demonstrated a statistically significant correlation between UWT, degree of hydronephrosis and serum ESR values. Evaluation of serum CRP and ESR values could let us to predict the UWT, a parameter which is closely related with the degree of stone impaction.