Medical titanium produced by Titanium Wire Corporation (grade IV) was the subject for analysis. The mechanical treatment of subjected titanium pieces was carried out with the use of sand - blasting. One sand - blasted titanium cylinder was left as the control one. The others were subjected to acid – etching in different acid mixtures. The enlargement of the titanium surface area was estimated by measuring of surface roughness. This factor is described by average roughness Ra which is an internationally recognized amplitude parameter defined as an arithmetic mean of departure of the roughness profile from the mean line. After modifications all samples were soaked in Simulated Body Fluid. Adsorption of calcium phosphate on modified surface is the expression of the biological properties of this surface. The results indicate that there is no direct correlation between adsorption of calcium and phosphorus and surface roughness expressed by Ra parameter.