We investigated spark-induced ignition of methane/air- and propane/air-mixtures under turbulent conditions in a pipe-flow system where turbulence was increased by, the use of grids. A laser-doppler-anemometer was used to characterize turbulence in the test facility, To determine the actual energy released by the spark ignition source, we measured electrical current and voltage during spark discharge. The results show that turbulent fluctuations have the greatest influence on the ignition process, whereas the convective pail of the flow (tip to velocities of 40 m/s) averts little influence. For numerical work, a one-dimensional simulation program, including detailed chemistry and multi-species molecular transport is used. It is shown that the main influence on the ignition is due to the rms-value of turbulence. Furthermore, the influence of increased flow velocity, on flammability, limits, and of different spark duration times and macrolengths on the ignition process, are demonstrated.