The present paper examined the effects of different background sounds on counting performance. Two experiments were carried out to test how counting performance was affected by four background noise conditions: spoken numbers, numbers played backwards, names of occupations and a silent control condition. The hypothesis was that the condition with spoken number noise should have strongest negative effect on counting performance. The results from Experiment 1 gave no support for the hypothesis, since no significant difference between conditions was found. Experiment 2 used a more complex counting task and a faster presentation rate of the background sounds. The condition with spoken number noise showed largest effect on counting performance, and performance in the control condition was better than all background sound conditions. The results are in line with the theory of interference by process.