Study Design: Experimental and control group design utilizing randomized clinical trials using pre-post intervention repeated measures. Objectives: To determine the effects of foot orthotics on quadriceps angle (Q-angle), knee pain and function in a patellar-femoral population with pronated feet, and whether a Merchant view patellar congruence angle can predict the effectiveness of an orthotic. Background: Foot orthotics are commonly used for correction of alignment in a foot pronation population with patellofemoral pain. It is unclear if custom semi-rigid foot orthotics alter knee pain, change standing Q-angle, improve knee function, or if there is a correlation between Merchant x-ray views of the patella and the ability to predict the orthotic’s effectiveness. Methods and Measures: Sixty volunteer experiencing anterior knee pain were randomly assigned to treatment group receiving bilateral custom semirigid foot orthotics plus home exercise program, and control group HEP only. Pre/post intervention repeated measures were used for: (1) Q-angle measurement in standing; (2) pain as assessed by visual analogue scale (VAS); (3) Lower Extremity Function Scale (LEFS) questionnaire; and, (4) Merchant view patellar x-ray angles when available. Results: Paired t-test showed the custom orthotic group had significantly less pain and significantly higher function than the non-orthotic group after the 28 day trial. Significant changes in Q-angle were measured between barefoot and athletic shoes plus orthotics. No correlations were noted between Merchant view x-rays and orthotic success. Conclusions: Custom semirigid orthotics diminish pain and Q-angle, and improve function for patients who experience patellar-femoral pain and foot pronation.