Add the frozen pierogies to the slow cooker. Add the kielbasa, cubed cream cheese and cheddar cheese on top.
Pour over the chicken broth.
Cook on LOW For 4 hours. Don't cook any longer than four hours or the pasta may fall apart. Turn off the slow cooker promptly after cooking time is up.
The sauce may seem seperated, it's just the cream cheese. Simply stir until the sauce somes together, gently.