We studied a population of 47 patients who were admitted to Alassad Hospital in Latakia with Community-Acquired Pneumonia from April 2013 to April 2014 , 21 women and 26 men, they were followed up every 48 hours over eight days. Patients were divided into three groups according to clinical stability criteria, and we studied the changes in CRP values at each group of patients separately and found the following: RapidResponse 25.5%: the value of CRP decreased on the fourth day by 48.1% SlowResponse 38.3%: the value of CRP in the fourth day decreased by 14.1% but fell on the sixth day by 35.7%TreatmentFailure 36.2% : the value of CRP have not fallen on the fourth day, but became 103%. on the sixth day decreased slightly by 5.9%, on the eighth day fell by 39%. Conclusion: CRP changes Coincided with the patients' response to treatment well so they can be relied upon (In addition to the other stability criteria but not alone) in determining the type of response and thus making a decision about the treatment plan.