Although research into evaluative conditioning (EC) has progressed considerably over the past 30 years, there have been some doubts about the strength and reliability of conditioning effects ¿ especially when visual stimuli are used. Partly this has been due to well-documented methodological debates and empirical evidence of alternative causes of apparent learning (Field & Davey, 1999). The seeds of doubt have undoubtedly been nurtured, also by the numerous informal reports of researchers failing to obtain EC effects ¿ even when replicating previously successful paradigms. This has led some to talk of boundary conditions that could enhance or eliminate the effects in EC experiments (De Houwer, Baeyens, Vansteenwegen & Eelen, 2000). This paper summarises 12 experiments that have explored this elusive phenomenon with mixed results (even when replicating past procedures). These various experiments are used to attempt to draw conclusions about what boundary conditions might exist for evaluative conditioning.