The porosity of various thermally sprayed coatings was determined using an Archimedian Method. The method relies on density determinations and buoyancy effects. First, measurements were carried out on standard samples in order to verify the accuracy and reliability of the Archimedian method. Then, porosity measurements were taken for hydroxyapatite samples and correlated to its physical properties. The results from the experiments show that as the crystallinity of the HAp increases, the porosity increases. Also, as the amorphous content increases, porosity decreases. Other relationships indicated that the porosity decreased as the stand off distance increased and it decreased with a power increase.