In chronic coronary occlusions the rate of successful reopening seems to be improved with the help of new techniques; the chance of success can be judged by the age of occlusion. Frequently this age cannot be fixed exactly. The purpose of the study was therefore to find out, whether the chance of reopening can be judged by morphology. 60 patients in whom the occlusions could not be passed with a conventional wire were treated with the ROTACS system. Cine angios were reviewed carefully, morphological details in at least two projections were evaluated in graphic representations and correlated with the acute success rate and the estimated age of occlusion. Morphological parameters associated with a higher rate of success (type A) were: 1) a clearcut proximal stump with 2) no sidebranches at the site of occlusion, 3) no bridging collaterals and 4) only a slight filling of the distal vessel. Parameters with a low success rate (type B) were: 1) no proximal stump, 2) sidebranches at the site of occlusion, 3) bridging collaterals and 4) a very good distal filling. 48/60 (80%) of occlusions could be classified in type A or type B. The success rate was 17/21 (81%) (type A) versus 5/27 (18.5%) (type B) (p < 0.0002). The estimated age of type B occlusions was significantly higher than in type A: median 8 versus median 4 months (p < 0.002). It is concluded that the rate of success in reopening chronic coronary occlusions can be judged in the majority of patients using morphological parameters.