We extend some results about shifted Schur functions to the general co
ntext of shifted Macdonald polynomials. We strengthen some theorems of
F. Knop and S. Sahi and give two explicit formulas for these polynomi
als: a q-integral representation and a combinatorial formula. Our main
tool is a q-integral representation for ordinary Macdonald polynomial
. We also discuss duality for shifted Macdonald polynomials and Jack d
egeneration of these polynomials.