Background: There are many performance obstacles in intensive care units (ICU) that can waste a nurse's time and energy. Detection and elimination of these obstacles can improve efficacy in ICUs. Objectives: This study was carried out to identify the performance obstacles experienced by nurses in ICUs of selected hospitals in Kashan/Iran, 2015. Methods: In this descriptive analytical cross-sectional study, all 80 nurses working in ICUs reported their performance obstacles in 240 working shifts. The research instrument had 2 parts: 1-information of nurses and their working shift; 2-nursing performance obstacles questionnaire of Gurses. The questionnaire evaluates performance obstacles in 4 dimensions of environment, task, technology, and organization. The data analyzed with the descriptive and analytical statistics including Mann-Whitney U and Krukall-Wallis tests, and multiple regression analysis using SPSS 16. Results: The most common obstacles were: receiving too many phone calls from family members (75%), delay in getting medications from pharmacy (54.6%), insufficient space to sit down and do paperwork (52.9%), and disorganized unit (51.6%). In the field of technology, having to use equipment in poor condition (35%) was the most frequent obstacle. Delay in seeing new medical orders (48.3%) and inadequate information from physicians (30.4%) were other common obstacles. The nurses with less than 3 years of experience working in ICUs, those working morning shifts, and nurses who had admitted more patients reported significantly more obstacles. Conclusions: Nursing performance obstacles were different. Many obstacles such as receiving too many phone calls and having to use equipment in poor condition can be managed by simple interventions such as using technology to give information to the family members. Management policies and enhancing team works are needed to reduce obstacles such as inadequate information from physicians and disorganized unit. We need further studies, to evaluate how the elimination of these obstacles can improve the nursing care in ICUs.