Background: Young children's mathematics abilities may be divided between symbolic and non-symbolic skills. Lower performance of SES disadvantaged versus advantaged children has already been established in symbolic math. Aim: This study aimed to verify the effect of children's SES category on non-symbolic mathematical (numerical) performance. Sample: The main sample comprises 4,955 children from the French longitudinal study, ELFE, tested when they were in the nursery school (4- to 5-year-olds). Method: The distinction between symbolic and non-symbolic math skills based on the specific math assessment items used in the present study was verified on a larger sample. The SES-related difference in non-symbolic math skills was then examined in the ELFE sample only. Results: The children's performance in non-symbolic maths is significantly and almost as strongly correlated with their family's income and their mother's level of education as their performances in symbolic maths. Linear regression mixed-effects modelling shows that the score in non-symbolic maths (out of 100) of children from families with below median income is 3.8 points lower than that of their peers from families with above median income. Conclusion: Children from disadvantaged SES backgrounds perform significantly lower than those from advantaged backgrounds in non-symbolic maths. Even if non-symbolic math skills retain an educational interest, they should not reduce the importance of symbolic math skills in young children.