In this paper, we analyze the relationship between personal opinions about the social security
system and levels of informal employment using data from a recent household survey carried out in
Bulgaria. We compare different indicators of job informality, focusing on the lack of social
security affiliation as the main indicator. Our results suggest that low value is attached to social
security affiliation and that knowledge of the social security system is very limited. As a
consequence, many workers seem to choose informal jobs because they think that the benefits from
being affiliated with the social security system are too low compared with the costs. On the other
hand, being affiliated does not seem to matter in terms of overall job satisfaction.