The magneto-caloric effect (MCE) of arc-melted bulk and 10 h ball-milled nanostructured Pr(2)Fe(17) powders has been investigated. The maximum value for the magnetic entropy change, vertical bar Delta S(M)vertical bar, in the milled alloy is 4.5 J kg(-1) K(-1) for mu(0)H = 5T, at around room temperature. The full width at half maximum, delta T(FWHM), of vertical bar Delta S(M)vertical bar(T) for the nanostructured powders is about 60% greater than that of the starting bulk alloy, thus giving rise to large relative cooling power values of 573 J kg(-1) (4.5 J cm(-3)) for mu(0)H = 5T estimated from the product of vertical bar Delta S(M)vertical bar(max) x delta T(FWHM). These results have been compared with those of well-known magnetic materials that exhibit a large or giant MCE effect. The potential for using these low-cost iron based nanostructured Pr(2)Fe(17) powders in magnetic refrigeration at room temperature is also discussed.