The traffic on inland waterways takes place as passenger or freight traffic. In Republic of Croatia, inland waterways take just a small part of the total traffic transport and the most of it is freight transport. Because of their many financial and ecological advantages, the development of inland waterways are very important. This paper is based on the analysis of the current state of Sava river waterway which doesn't meet the demands of IV. class through whole river section and the current state of freight transport. Harbour Sisak and Slavonski Brod are also studied as only croatian harbours on Sava river. Proposed development of the Sava river waterway as part of an intermodal transport network is based on various studies and strategies. This would greatly increase traffic on the Sava river by making adequate intermodal terminals which would put Sava river as a competitive transport route in the transport market.