Introduction: Today, the complex organizations and institutions may not survive without a precise planning as well as selecting the appropriate approach, which requires accurate knowledge about the situation of the organization. Functional analysis enables these organizations to implement the strategies which strengthen the internal strengths and reduce or eliminate the internal barriers and weaknesses. In order to promote the hospital activities, this study was aimed to analyze the internal environment of Khatam Alanbia Hospital based on Weisbord's model for organizational diagnosis. Materials and Methods: This cross-sectional and descriptive–practical research has been performed in Khatam Alanbia Hospital in Tehran on 2014. The data were compiled from the standard organizational diagnosis questionnaire and Weisbord's six-dimensional model. The investigation was conducted on 312 out of 1645 staff of Khatam Alanbia Hospital. Data analysis was performed by SPSS, version 19, descriptive statistics and one tailed t-test. Results: The results showed that there was a positive significant relation between different dimensions. Between the all internal dimensions, rewarding had the highest score and organizational purposes had the lowest score. Conclusion: Regarding the magnitude and complexity, no organization is like a hospital. Therefore, conducting periodically investigation in order to have a better understanding of the organization, to make appropriate decisions, and to improve the performance and efficiency of the hospital is recommended. Without an appropriate overview, it is impossible to adopt effective decisions.