We have investigated the interplay between glycolytic oscillations and intracellular K ⁺ concentration in the yeast S. cerevisiae. Intracellular K ⁺ concentration was measured using the fluorophore PBFI. We found that K ⁺ is an essential ion for the occurrence of glycolytic oscillations and that intracellular K ⁺ concentration oscillates synchronously with other variables such as NADH, intracellular ATP and mitochondrial membrane potential. We also investigated if glycolysis and intracellular K ⁺ concentration oscillate in a number of yeast strains with mutations in K ⁺ transporters in the plasma membrane, mitochondrial membrane and in the vacuolar membrane. Most of these strains are still capable of showing glycolytic oscillations, but two strains are not: (i) a strain with a deletion in the mitochondrial Mdm38p K ⁺/H ⁺ transporter and (ii) a strain with deletion of the late endosomal Nhx1p K ⁺/H ⁺ (Na ⁺/H ⁺) transporter. In these two mutant strains intracellular K ⁺ concentration seems to be low, indicating that the two transporters may be involved in transport of K ⁺ into the cytosol. In the strain Mdm38p Δ oscillations in glycolysis could be restored by addition of the K ⁺/H ⁺ exchange ionophore nigericin. Furthermore, in two non-oscillating mutant strain with a defective V-ATPase and deletion of the Arp1p protein the intracellular K ⁺ is relatively high, suggesting that the V-ATPase is essential for transport of K ⁺ out of the cytosol and that the cytoskeleton may be involved in binding K ⁺ to reduce the concentration of free ion in the cytosol. Analyses of the time series of oscillations of NADH, ATP, mitochondrial membrane potential and potassium concentration using data-driven modeling corroborate the conjecture that K ⁺ ion is essential for the emergence of oscillations and support the experimental findings using mutant strains.