CNOISE is a C library which generates sequences that simulate 1/f^alpha power law noise. This includes white noise (alpha = 0), pink noise (alpha = 1) and red or Brownian noise (alpha = 2), as well as noise for values of alpha between 0 and 2, by Miroslav Stoyanov. CNOISE is based in part on an algorithm by Kasdin, as cited in the references. Kasdin’s implementation referenced a number of functions from the Numerical Recipes library (FOUR1, FREE_VECTOR, GASDEV, RAN1, REALFT, VECTOR). Numerical Recipes is a proprietary library whose components cannot be freely distributed. The implementation given here relies instead on the free source library ”GSL” (the GNU Scientific Library). Thus anyone can build the code without requiring access to restricted or proprietary software.