The current study aimed to be an empirical test of E-Prime theory regarding its alleged positive effects of eliminating the verb “to be” from speech. Therefore, we investigated the intensity and the direction of the association between the frequency of using the verb “to be” and various psychological outcomes, namely general rational and irrational beliefs, negative functional and dysfunctional emotions, the functionality of inferences, and general psychological distress. 197 participants completed measures of investigated variables. Multiple Pearson product-moment correlations were used to test our hypothesis within a cross-sectional design. The frequency of using the verb “to be” was significantly negatively associated with levels of general rational beliefs, r = − .211, p = .021, and also with levels of preference beliefs, r = − .251, p = .003. This study provides first evidence in favor of E-Prime’s assumption that a less frequent use of the verb “to be” can lead to a less rigid and non-judgmental style of thinking. The elimination of the verb “to be” from speech may prevent dogmatic or rigid thinking, thus stimulating flexibility, and in turn determine the increase of rational beliefs levels, especially the levels of preference beliefs. Possible clinical and scientific implications are discussed.