<b><i>Background:</i></b> Pain is the most common symptom, which is often experienced in acute illnesses and is one of the symptoms that patients feel apprehensive about. Undertaking pain management aims to prevent negative physiological and psychological outcomes. Inadequate knowledge about pain and its characteristics is a common barrier to effective pain management. Evidence shows that if nurses have adequate knowledge and a positive attitude towards pain, it may lead to more effective pain management. <b><i>Objectives:</i></b> The main goal of this study is to assess the effect of nursing in-service education program on nurses’ knowledge and attitudes concerning pain management in one of the governmental hospitals in Dubai, United Arab Emirates. <b><i>Methodology:</i></b> This study has a quantitative-experimental, random assignment design with a pre-test/post-test approach used in one of the governmental hospitals in Dubai, United Arab Emirates. The study was carried out between February and April 2019. The sample of this study consisted of 200 participants selected randomly from the units in the hospital by simple randomization through the software SPSS version 20. The experimental group received the pain management program (PMP) over 5 h. The participants were exposed to a pre-test and after receiving the PMP, they were administered the post-test, while in the control group the pre-test and the post-test were carried out without intervention. <b><i>Result:</i></b> The paired <i>t</i> test was used to find the mean difference between pre- and post-intervention. The findings of the experimental group revealed that the mean score on the Knowledge and Attitudes Survey Regarding Pain (KASRP) increased after the intervention from 61.36 (SD 11.60) to 69.94 (SD 7.74) with a mean difference of 8.58 (<i>t</i>(99) = –5.97, <i>p</i> < 0.05), while in the control group the mean score on the KASRP slightly decreased following the test (mean ± SD, 60.99 ± 11.53%) compared to the pre-test (mean ± SD, 61.00 ± 11.60%) with a mean difference of 0.01 (<i>t</i>(99) = 1.41, <i>p</i> > 0.05). <b><i>Conclusion and Recommendation:</i></b> In-service education PMP proved to be effective. Pain knowledge and attitudes were improved after the educational session. Nurses in the experimental group scored higher in the post-test but still did not reach the passing score of 75%. Moreover, the knowledge scores increased significantly after implementing the PMP. As concluded from the current study, well-structured in-service education sessions are able to improve knowledge and show an impact on attitude changes. Since the PMP proved to be effective, it is recommended to be implemented in daily nursing practice.