The study aims to explore to what extent scientific institutions in Poland implement open access through their procedures and practices. Using data from an on-line survey (N=197) we selected eight variables reflecting open science practices. Two-step clustering was applied to explore patterns in the data. The analysis allowed us to identify four profiles of institutions: the least advanced in open science practices, small, teaching- or research-oriented institutions, two groups of institutions implementing open science practices to a limited extend, and a cluster of institutions with the most advanced and comprehensive practices in this field.