In this paper, the possibility of using natural rubber in the design of a simple flexible patch antenna is reported for the first time. The antenna was designed to operate at an arbitrary frequency of 10 GHz, and the effects of substrate thickness and permittivity, and metal thickness were studied. Our results show that the return loss of the antenna can be improved by decreasing the substrate thickness and permittivity. In contrast, decreasing the metal thickness will increase the return loss. It was noted, too, that using thicker substrates will give higher directivity, and that low εr will result in lower directivity. Hence, some trade-off between these parameters is required for optimal design. In conclusion, our studies show that natural rubber has potential for use in flexible microstrip antennas. Work is currently in progress to build prototypes of the said antenna, and their performance will be reported in future communications.