Aerobic glycolysis, which is also termed the Warburg effect, is one of the aberrant metabolic pathways in highly proliferating cells. Glycolysis provides glycolytic metabolites to support the generation of biomass, such as nucleotides, amino acids, and lipids. To date, no studies have explored interrelationships between glycolysis and other metabolic pathways. Phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) activates glycolysis by synthesizing fructose-2,6-bisphosphate (F2,6BP), which allosterically activates the rate-limiting enzyme 6-phosphofructo-1-kinase (PFK-1). In this study, we found that PFKFB3 directly interacts with and regulates the phosphorylation of carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (CAD), the enzyme catalyzing the first three steps of de novo pyrimidine synthesis. PFKFB3 inactivation reduced de novo pyrimidine synthesis, RNA and DNA production, and the growth of cancer and proliferative cells. Thus, the glycolytic activator PFKFB3 bridges glycolysis with pyrimidine synthesis, unites both glucose metabolism and nucleic acid metabolism, and contributes to cell proliferation under both physiological and pathological conditions.