The present study was designed to compare the content of 113 suicide notes from attempted suicides, completed suicides and a nonsuicidal group asked to write possible suicide notes. The content analysis examined formal, syntactical and grammatical characteristics, as well as speech patterns and verbal expressions. The letters from attempted and completed suicides had five significant differences. The notes from completed suicides had higher scores for evaluators, hetero-aggression (blaming others) and nonpersonal references and lower scores for expression of feelings and adverbial intensifiers. Differences by sex and age were not statistically different. Regarding the combined suicide notes vs controls, the control texts had lower scores for all categories except word count (no significant differences) and “We” (the controls texts had more references to “we”). The suicide notes, therefore, had more indications of irrational thinking, characterized by high scores for emotional categories, frequent negation, and absolutistic words, high self- preoccupation and a tendency toward polarized thinking These results may help the understanding of suicidal phenomenon and its dynamic background, as well as aiding risk assessment.