The aim of the current research is to know the effectiveness of designing the e-content that is based on learning objects and its effect on the development of some of the mathematical concepts Kindergarten children in State of Kuwait. The study instrument was a mathematical concepts pre and post tests. The research sample was (38) male and female children that were divided randomly into two groups experimental and controlled. The researcher applied the experiment in a month from 16-11-2015 until 17-12-2015. The researcher used a number of statistical methods to analyze the results. The results showed the effectiveness of designing the e-content that is based on learning objects in the development of the mathematical concepts among Kindergarten children when the effect of the mathematical concepts pre test and the grades were controlled. The experimental group achieved 90 %.