  We construct instanton solutions on noncommutative Euclidean 4-space which
are deformations of instanton solutions on commutative Euclidean 4-space. We
show that the instanton numbers of these noncommutative instanton solutions
coincide with the commutative solutions and conjecture that the instanton
number in R^4 is preserved for general noncommutative deformations. We also
study noncommutative deformation of instanton solutions on a T^4 with twisted
boundary conditions.
