The high pressure melting curve of tin was measured to 45 GPa using a designer diamond anvil cell with an integrated internal resistive heating element. Melting of the tin sample was detected by an abrupt increase in the electrical resistance of the sample and also by a change in the slope of the electrical heating power versus temperature curve. The melting temperatures determined by these two methods are in good agreement with each other. We find that the melting temperature of tin tends to monotonically increase with increasing pressure and reaches a temperature of about 2000 K at 45 GPa. © 2012 American Institute of Physics.