Endotracheal suctioning is a crucial element in the management of the airway in intensive care units. The effectiveness and complication of the endotracheal suctioning procedure is associated with the method of performing. The procedure requires clinical expertise, so the nurses should perform this procedure safely and effectively. The present study was carried out to assess the gap between knowledge and practice in standard endotracheal suctioning of intensive care unit nurses. In this cross sectional descriptive study knowledge and practice of 118 nurses in the 11 ICU’s of children hospital Lahore, Pakistan was analyzed. The sampling method is purposive. Data were collected using 35 item questionnaire and 31 item checklist. Descriptive and inferential statistics was used to analyze the data. The result of the study revealed that the participant have good level of knowledge (mean score 24 ±3.0) and fair level of practice as (mean practice score was 17.85± 5.67) showing that there is a gap between knowledge and practice. There is no relationship between knowledge and practice score. Significant relationship was found between practice score, total experience (p=0.007) and ICU type (p=0.004). The study describes that despite the presence of good knowledge their practice level is not up to the mark. The result shows that there is a need for training in this skill and continue feedback until desire level of skill achieved.