Mental health symptoms in military populations are rising and constitute a significant health concern. This study examined the prevalence of depression, anxiety, and suicidal ideation in soldiers (N = 3,792) undergoing combat medic training. At the start of training, 10.4%, 15.5%, and 4.1% of soldiers had clinically significant depression, anxiety, or suicidal ideation, respectfully. These percentages increased to 12.2%, 20.3%, and 5.7% at completion of training, respectfully. Worsening of depression, anxiety, and suicidal ideation occurred for 7.7%, 11.4%, and 4% of soldiers. Higher percentages of symptoms were associated with females, lower education, and lower income. Active duty personnel were more likely to worsen following training with respect to suicidal ideation (OR = 1.9, 95% CI = 1.2-2.9) compared to reservists. The identification of these significant predictors of mental health status may serve to identify individuals at risk. Additional work to examine the relative contribution of anticipatory (impending deployment) factors vs. training-related factors is warranted.