Background: Anxiety is an outcome of a stressful work environment, like the clinical environment, which decreases the mental health level and delays the provision of services to patients. Objectives: This study examined the effects of resilience skills training and metacognitive therapy on nurses’ anxiety working in Intensive Care units (ICUs) and Emergency Department (ED). Methods: This randomized controlled field trial was carried out on 54 nurses working in ICU, PICU, NICU, and ED of Valiasr Hospital, Birjand, Iran. The participants were allocated via permuted-block randomization into three groups of resilience, metacognitive therapy, and control. Research instruments included a demographics form and the Spielberger anxiety inventory. Parametric statistics (e.g., ANOVA, repeated-measures ANOVA, Chi-square, and Fisher’s exact test) were used for data analysis in SPSS (V.19) (P < 0.05). Results: In the resilience group, the mean scores of trait and state anxiety significantly decreased immediately and one month after the intervention compared to before the intervention (P < 0.001). However, there was no significant difference in the metacognitive therapy group in terms of the mean score of trait and state anxiety at the three stages of the study (P > 0.05). There were significant differences between the three groups in terms of trait and state anxiety mean score changes before and immediately after the intervention, as well as before and one month after the intervention (P < 0.05). Conclusions: Resilience skills training was more efficient than metacognitive therapy in the attenuation of anxiety in ICU and ED nurses. Nursing managers are proposed to hold resilience skills training to control nurses’ anxiety.