To explore the associations between social networks, social contacts, and cognitive impairment in the very elderly aged 90-108 years.Data were from subjects of the Project of Longevity and Ageing in Dujiangyan, China. The socio-demographic, social networks, and social contacts data were collected and cognitive function was assessed in all subjects using the Mini-Mental State Examination (MMSE).764 Chinese nonagenarians and centenarians (67.41% women, mean age 93.47 years) were included. The mean MMSE score was 14.99 ± 5.93). The prevalence of cognitive impairment was 64.53%. The mean social contact score was 4.37 ± 1.86. There were significantly different cognitive function scores among individuals with different marital status, number of close friends, and different social contact levels (all P<0.05). Spearman rank correlation analysis showed that number of close friends and social contact scores were significantly positively but single status was significantly negatively correlated with the MMSE scores (all P<0.05). Multiple logistic regression analysis showed that there were associations between single status, no close friend, and low level of social contact with cognitive impairment (all P<0.05), but not other social network variables.Single status, no close friend, and low level of social contact were associated with increased risk of cognitive impairment in Chinese nonagenarians and centenarians. Our finding might add new information for social networks, social contacts, and cognitive research in the elderly.