Abstract: An outbreak of dengue fever type Ⅰ occurred in Guangzhou from Apirl to November,1995.A total of 5505 cases were reported.The incidence rate was 84.24 per 100,000.No death case was reported.The first patient was confirmed on Apirl 10.Sporadic cases were found in May to June.Most of the cases appeared in August to September,which accounted for 91 percent of all cases.There were 13 foci,which involved 7distrits and a county. Shawan town was a main focus where 4972 cases occurred.12 strains of dengue type I virus were isolated from 117 cases of acute - phase patients were serologically confirmed as dengue fever.Epidemiological investigation revealed that the preventive measures in urban districts were effective for controlling the disease,however,the measures for the rural area should be strengthened.