The objective of this study was to determine levels of knowledge regarding domestic violence (DV), and the effectiveness of formal instruction about DV. A general knowledge survey of DV was given before and approximately 4 to 6 months after 3 hours of instruction given by Emergency Medicine and Law Enforcement faculty. A Emergency medical service (EMS) consisting of 73% paramedic-level providers in a metropolitan urban/suburban area. Differences in DV knowledge before and after the instruction were the main outcome measures. In the preinstruction series, 46 emergency medical technicians (EMTs) participated. After the instruction 19 EMTs participated (42%). Thirty-five percent of EMTs before instruction and 37% after instruction correctly identified the prevalence of DV against women as 15% to 30%. Thirty-five percent of EMTs before instruction and 63% after instruction (P < .05) correctly identified the prevalence of DV against men as 0% to 15%. Before instruction 54% knew that DV is equal among races, and 79% after instruction (P < .05). Before instruction 37% of EMTs knew that DV is equal in different socioeconomic groups and 68% after instruction (P < .05). The percent of EMTs who knew that the victim is not responsible for the abuse was 50% before instruction and 89% after instruction (P < .05). Before instruction, the results on a knowledge questionnaire were 54% correct, after instruction, results improved to 71% correct. Improvement in understanding of DV was shown for 4 of 11 questions after 3 hours of instruction. These results indicate the need for more instruction on DV for EMTs.