Abstract: We have collected a sample of 69 radio-loud quasars from various references.The sample includes 37 SSRQs (with α>0.5) and 32 FSRQs (with α<0.5) with redshifts ranging from about zero to about two.We have carried out an analysis of statistical correlations between black hole spin values and radio-loudness indices for the sample.In the analysis we consider three cases of the spin values.The three cases correspond to three different assumptions about the magnetic field strengths around the black holes.Our conclusions are as follows.(1) In SSRQs their black hole spin values are strongly correlated with their radio-loudness indices;(2) The correlation in SSRQs is not caused by relativistic beaming;(3) There is no indication of a strong correlation between supermassive black hole mass values and spin values for FSRQs;(4) The correlations between black hole spin values and radio-loudness indices may be different for different types of radio-loud quasars.Our results are consistent with models of radio-loud quasars of other authors.