To study the differential educational effects of a multimodal educational program on public stroke knowledge, we performed computer-assisted telephone surveys among a random sample of 500 members of the general public, before and immediately after an intense three-month educational campaign. The intervention comprised of poster advertisements, flyers, mail circular, slogans, stroke interest stories etc. in local newspapers, on television and radio, and public events. The main outcome measures were stroke knowledge, the intended behavior in acute stroke and the educational media remembered after the intervention. General knowledge of the nature of stroke (65.7% correct answers before versus 84.9 % after the campaign, p < 0.01) and the awareness of being at risk of stroke (32.7 % vs. 41.9%, p < 0.01) increased due to the campaign, especially in respondents of lower educational background. There was no significant effect on the number of patients who would seek emergency medical care after the intervention (81 % vs. 82 %) and hardly any effect on detailed knowledge of stroke warning signs or different risk factors. Mass media like newspapers, radio and television were most frequently reported as the main information source remembered (66.6 %). Our data indicate that educational programs do have differential effects on public stroke knowledge and individual stroke risk,which does not necessarily lead to a change in care-seeking behavior. Repeated information using short-tailored slogans and cues to action led to a gain in general stroke knowledge, especially in high-risk populations of lower educational background. Large educational campaigns seem unsuitable, however, for mediation of detailed information on stroke.