A new quantum deformation, which we call null-plane, of the (3+1) Poin
care algebra is obtained. The algebraic properties of the classical nu
ll-plane description are generalized to this quantum deformation. In p
articular, the classical isotopy subalgebra of the null-plane is defor
med into a Hopf subalgebra, and deformed spin operators having classic
al commutation rules can be defined. Quantum Hamiltonian, mass and pos
ition operators are studied, and the null-plane evolution is expressed
in terms of a deformed Schrodinger equation.