To what extent are death- and life-oriented psychological processes among suicidal individuals activated by mood? According to Teasdale’s (1988) Differential Activation Hypothesis, we would expect that negative mood-activated psychological processes are maladaptive among suicide ideators (vs. non-ideators) and predictive of subsequent suicidal ideation. This, however, has never been prospectively studied. To address this knowledge gap, we conducted a prospective study assessing psychological risk factors via the Death/Life Implicit Association Test (IAT) and the Suicide Stroop task before and after a temporary negative mood induction. Suicidal ideation was assessed one and six months later. Results based on Death/Life IAT performance largely supported hypotheses, such that suicide ideators demonstrated significantly weaker implicit identification with life after (vs. before) the negative mood induction. Non-ideators demonstrated no significant change, maintaining strong identification with life irrespective of mood. Of note, this baseline interaction may have been accounted for by depressive symptoms. Identification with death (vs. life) predicted greater likelihood of suicidal ideation one month later, controlling for depressive symptoms and baseline suicidal ideation. Only negative mood-activated identification with death predicted suicidal ideation six months later. Suicide Stroop scores did not change as a function of mood or predict subsequent suicidal ideation. Death/Life IAT findings support the Differential Activation Hypothesis and suggest that suicide ideators’ identification with life is more variable and easily weakened by negative mood relative to non-ideators. We encourage future work to consider the potential role of transient mood and the importance of measuring psychological processes that pertain to both death and life.