Limited data exists to date on the predictors for the development of pneumonia in patients with mild and moderate coronavirus (COVID-19). In this study, it was aimed to evaluate the demographic characteristics and clinical findings of mild and moderate COVID-19 and to determine the risk factors for the development of COVID-19 pneumonia in patients admitted to the pandemic outpatient clinic of a university hospital. A total of 414 patients with laboratory confirmed COVID-19 were included. Of these, 220 (53.1%) were male, the mean age was 38.3 +/- 12.7. Median duration of hospital admission from the onset of symptoms was three days (0-11). Of the confirmed COVID-19 cases, 154 (37.2%) had a history of family contact and the most common symptoms were weakness (68.4%), myalgia (61.8%), headache (56.5%), loss of smell (45.2%), loss of taste (43.2%) and anorexia (42.8%). Among females, weakness (p= 0.016), headache (p= 0.008), sore throat (p= 0.032), nausea (p= 0.003), anorexia (p= 0.045), loss of taste (p= 0.005) and loss of smell (p< 0.001) were more common. Loss of taste (47.6% vs. 25%, p< 0.001) and loss of smell (50% vs. 26.3%, p< 0.001) were more common in patients with under the age of 50 and cough (43.4% vs. 29.3%, p= 0.003) was more common in patients with above the age of 40. Among 46 (11.1%) patients with asymptomatic COVID-19, there was no significant difference (p= 0.500) between the genders. Pneumonia was detected in 150 (43.8%) of 339 patients who underwent thorax computed tomography. In the univariate analysis; advanced age (p< 0.001, odds ratio (OR)= 1.44), obesity (p< 0.001 OR= 2.5), not being actively smoking (p< 0.001, OR= 6.19), fever at first admission (p= 0.002, OR= 2.02), cough (p< 0.001, OR= 3.26), shortness of breath (p< 0.001, OR= 23.37), weakness (p= 0.042, OR= 1.63), anorexia (p= 0.009, OR= 1.79) and elevation of D-dimer (p= 0.014, OR= 1.92) were associated with the development of pneumonia. In multivariate analysis, obesity (p= 0.005, OR= 2.69), not being actively smoking (p< 0.001, OR= 5.43), cough at first admission p= 0.017, OR= 2.16) and shortness of breath (p= 0.008, OR= 16.22) was determined as an independent risk factor for the development of pneumonia. CRP (p< 0.001), D-dimer (p< 0.001), ferritin (p< 0.001) values among 108 (26.1%) patients with a body-mass index(BMI) >30 were high, and 60.9% of the patients had pneumonia (p< 0.001). CRP (p< 0.001), D-dimer (p= 0.010) values were low, lymphocyte count (p= 0.001) was high among 106 (25.6%) active smokers, and 15.6% of the patients had pneumonia (p< 0.001). Of the patients reported with persistent symptoms, 25.9% had loss of smell, 25% had weakness, and 23.1% had loss of taste on the seventh day; 21.1% had loss of smell, 21.1% had myalgia, and 19.7% had loss of taste on the 14th day. During their follow-up, the COVID-19 polymerase chain reaction (PCR) test was studied in 286 patients for control purposes. The median time of being negative for COVID-19 PCR test was eight days (3-56). In conclusion, symptoms may last longer than 14 days in 20-30% of patients presenting with mild-moderate clinical findings. In addition, obesity should be considered as an important risk factor for COVID-19 pneumonia.