Gastroesophageal reflux disease is an extremely common disorder. Only a small percentage of those patients seek medical advice. The interest in management of this disease increased markedly in the last few years. In this study, researches studied the role of lower esophageal sphincter pressure in the choice of treatment of gastroesophageal reflux disease (GERD). The primary outcome was symptom control after six weeks of pharmacological treatment with either proton pump inhibitors alone or proton pump inhibitors and Cisapride. This study was a randomized non-blinded clinical trial that included forty eight adult patients who presented with GERD-like symptoms. The following were done prior to randomization for treatment; detailed questionnaire and physical examination, esophageal manometry, 24-hour pH monitoring and Esophagogastroduodenoscopy (EGD). The treatment in group I was Omeprazole 20 mg twice a day, while in group II was Omeprazole 20 mg twice a day and Cisapride 10 mg four times a day. The response to treatment was noted after 6 weeks of treatment. The randomization for treatment was done based on the odd or even number of the patient. The study included 48 patients; with a mean age of 52 year-old, minimum age was 19 and maximum was 83 year-old. Female patients were 34 patients (64 %), compared to 16 males (36 %). Sixty nine percent of the patients were smokers and only 31 % were non-smokers. The Body mass index, which equals the weight divided by square the height, was used in this study. Fifty six percent of the patients were overweight (BMI > 30), while only 44% of the patients had BMI 30. 41 patients (85 %) presented with typical (esophageal) symptoms. 24 patients (50 %) had normal LES pressure, 18 patients (37 %) had low LES pressure, and 6 patients (13 %) had high LES pressure. The 24-hour pH monitoring showed mean time of pH < 4 of 9.2% of the time. The correlation between reflux symptoms and endoscopy (NERD), compared to 26 patients (54%) had evidence of esophagitis. The first group consisted of 32 patients (66 %) were treated with PPI alone, while, the second group was 16 patients (34 %) who received combined treatment. The symptom control after treatment was 88 % of the patients with Omeprazole alone and 94 % for combined treatment, however, this difference was not statistically significant. There were no statistical significance differnces between the two treatment groups prior to starting the experiment except for the smoking and the weight. The great similarity between the groups was quite helpful to explain that the outcome was mainly related to the treatment used. Patients were evaluated at the end of the treatment and there was no statistically significant difference between the treatment groups in control of symptoms after treatment. Also, LES pressure was not helpful in detecting the response to short-term treatment in any of the groups. In this study, LES pressure was not a statistically significant for predicting the outcome of GERD treatment. LES pressure didn't affect the outcome with use of different medications. There was no statistically significant difference in the response to treatment in relation to the duration of reflux detected by 24-hour pH monitoring. There was no statistically significant difference in response to treatment between erosive esophagitis (EE) and non erosive reflux disease (NERD).