BQCD (Berlin Quantum ChromoDynamics program) is a hybrid Monte-Carlo code that simulates Quantum Chromodynamics with dynamical standard Wilson fermions. The computations take place on a four-dimensional regular grid with periodic boundary conditions. The kernel of the program is a standard conjugate gradient solver with even/odd pre-conditioning. As a consequence all arrays are stored in an even/odd ordered fashion and the four indices are collapsed into a single one. The access to neighbours is handled by lists. The parallelization is done by a regular grid decomposition in the highest 3 dimensions. The values from the boundaries of the neighbouring processors are stored in the same array as the local values. The local values have indices 1, ..., volume/2. The boundary values have indices > volume/2. The memory for the arrays is dynamically allocated during initialization. Apart from rounding errors the program gives identical results for any grid decomposition. (Author of the code: Dr. Hinnerk Stueben).