Commuting represents the most important part of spatial mobility of people. Despite the fact of rising using of individual car transport, public transport belongs still to the most favourite mode of transport. This paper deals with evaluation of potential of public transport accessibility for purposes of commuting for three working shifts by public transport in the March of 2010. Valid time tables were used as a data source for analyses of the situation in municipalities in the Czech Republic with special focus on the Ostrava region. The ratio of accessible municipalities from all municipalities within 100 kilometres was used as a key factor for evaluation of municipalities’ accessibility. There is evident high level of correlation between high level of municipalities’ accessibility and location of important trunk roads or electrified railway lines in the Ostrava region. But it was proved, that a real commuting cannot be possible without sufficient possibility of return connection after the working shift. So the second part of this paper deals with two-ways commuting and quantifies the level of two-ways connections between municipalities.