To assess mental health utilization in Manhattan following the September 11th terrorist attacks, a random-digit-dial telephone survey was conducted 5 to 8 weeks afterwards, among 988 randomly selected adult householders over 17 years old (females = 52%; whites = 72%; mean age = 42). 16.9% (95% confidence interval [CI] = 14.4-19.5) of residents reported using mental health services 30 days before the attacks and 19.4% (95% CI = 16.7-22.2) reported using these services 30 days afterwards (pre/post NcMemar's chi2 = 8.0, df = 1, p = 0.005, odds ratio[OR] = 2.0). 10.0% (95% CI = 7.9-12.0) increased mental health utilization 30 days after the attacks, compared to 30 days before and 5.3% (95% CI = 3.7-6.9) decreased utilization. Risk factors associated with increased mental health utilization in multivariate analyses included: being 45-64 years of age (vs. 65+; OR = 8.3, p = 0.011) female gender (OR = 2.3, p = 0.004), experiencing 4+ lifetime traumatic events (vs. none; OR = 3.5, p = 0.002), experiencing 2+ stressful life events in the past 12 months (vs. none; OR = 3.3, p < 0.001), and experiencing an acute panic attack during the disaster (OR = 3.3, p < 0.001). Neither current post-traumatic stress disorder (PTSD) nor current depression was predictive of increased post-disaster utilization when panic attack was included in the multivariate analysis. While we did find a statistically significant increase in pre- vs. post-disaster utilization among the general population in Manhattan this increase was not substantial, except among specific subgroups, including those who had a perievent panic attack, among those exposed to previous stressors, among women, and among those less than 65 years old.