Abstract: Objective To investigate the weight gain in very low birth weight (VLBW)infants during hospitalization and its influencing factors.Methods Clinical data were collected retrospectively for VLBW infants admitted between January 1,2011 and December 31,2012 in Shenzhen Women and Children's Hospital.Weight gain and its influencing factors in VLBW infants during the hospitalization were analyzed by logistic regression and single factor analysis.Results A total of 147 VLBW infants were included in the study.The median of weight gain velocity(WGV)was 12.77 g/kg·d,and the incidence of extrauterine growth retardation(EUGR)was 62.6%.The infants in the moderate weight gain velocity(MWGV)group (P₅₀:56 d)had shorter duration of hospital stay than those in the low weight gain velocity (LWGV)and high weight gain velocity (HWGV) groups (P₅₀:48 d,3 6d).In addition,the incidence of EUGR in HWGV group(34.80%)was lower than that in the MWGV and LWGV groups(65.30%and 75.90%)(both P < 0.05).The results of logistic regression analysis showed that birth weight,time to regain birth weight,and time to achieve full enteral nutrition were related to the weight growth velocity.Conclusion Most VLBW infants have low WGV during hospitalization.Birth weight,time to regain birth weight and time to achieve full enteral nutrition are influencing factors for WGV in VLBW infants during hospitalization.