Abstract-A storing of spatial data and processing of spatial queries are important tasks for modern databases. The execution efficiency of spatial query depends on underlying index structure. R-tree is a well-known spatial index structure. Currently there exist various versions of R-tree, and one of the most common variations between them is node splitting algorithm. The problem of node splitting in one-dimensional R-tree may seem to be too trivial to be considered separately. One-dimensional intervals can be split on the base of their sorting. Some of the node splitting algorithms for R-tree with two or more dimensions comprise one-dimensional split as their part. However, under detailed consideration, existing algorithms for one-dimensional split do not perform ideally in some complicated cases. This paper introduces a novel one-dimensional node splitting algorithm based on two sortings that can handle such complicated cases better. Also this paper introduces node splitting algorithm for R-tree with two or more dimensions that is based on the one-dimensional algorithm mentioned above. The tests show significantly better behavior of the proposed algorithms in the case of highly overlapping data.