Chronic inflammatory diseases are common and still remain a therapeutic challenge for both efficacy and safety reasons. Hence, novel therapeutics addressing these issues would for example improve treatment of severe diseases such as psoriasis, rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis. Inappropriate leukocyte homing to the affected compartments is a common feature of these diseases. Heparin and related polysaccharides have been shown to interfere with leukocyte homing through a variety of effects distinct from their anticoagulant properties. In this review, data on heparin as an anti-inflammatory agent are presented. In addition, structure-activity requirements for the anti-inflammatory properties of heparin are discussed, which should aid the drug development based on structurally modified heparin or other sulfated carbohydrates for treatment of inflammatory diseases.