Abstract: A new method has been developed for easy and inexpensive determination of nuclear DNA content or genome size of plants. This method requires the determination of average cell volume, the number of cells present in a leaf tissue with known weight and intercellular space of the plant species. The nuclear DNA content in a single cell can be calculated easily by dividing the amount of genomic DNA present in a tissue section by the total number of cells in the same tissue. The genome size of five plant species has been determined both by this method and by flow cytometry. The results were found comparable from the accuracy point of view.