- Specialized training of medical teams for chemical warfare agent (CWA) events is important to save lives. We aimed to evaluate the retention of knowledge (ROK) and self-perceived competency (SPC) of military medical personnel in delivering treatment during CWA events. A questionnaire and a multiple-choice examination were sent to military physicians and paramedics, evaluating their CWA, ROK, and SPC (study group [SG]). Their assessment was compared to medical personnel immediately post training (reference group [RG]). SG was subdivided into two groups: G1 ≤ 1 year and G2 > 1 year, past training. Overall, 135 participants responded (35-RG, 65% physicians). Self-reported ROK and SPC were significantly higher in RG compared to SG and in G1 compared to G2. Test scores were higher in RG compared to SG, but similar in G1 and G2 groups. SPC was lower compared to ROK in the entire cohort and subgroups. A moderate correlation was found between the self-and test-assessed scores (Pearson correlation coefficient 0.45, p < 0.001). Physicians received significantly (p = 0.01) higher test scores in RG compared with paramedics. ROK and SPC among military medical personnel for treatment of CWA casualties deteriorate significantly as early as 1 year post training, SPC > ROK. Thus, we recommend CWA refresher training at least every year. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.