Objective To study the similarities and differences in growth and reproduction of Tlr 4 knockout and KM mice. Methods Twenty Tlr 4 knockout mice and 20 KM mice (half male and half female) were selected to measure body weight, body length, and growth rate from 4 to 12 weeks. Twenty cages were randomly selected with one female and one male in each cage. Statistical analysis was performed for the number of second born pups. Results The body weight and growth rate of Tlr 4 knockout mice were significantly lower than those of KM mice ( P < 0. 05), but there was no significant difference between 4 and 5 weeks in body length and growth rate. The body length and growth rate of Tlr 4 knockout mice at other periods were obvious. Tlr 4 knockout mice had a significantly lower reproductive ability than KM mice. Conclusions Tlr 4 knockout affects the growth, development, and reproduction of mice.