The subjective perception of professional self was studied for a sample of Medical Laboratory Technologists (MLTs) employed in Clinical Chemistry in Sweden. The sample (N = 488) consisted of a randomized tenth of members of their trade union. A mailed questionnaire with 21 items concerning self-description compared with peers in a seven-point Likert type scale was completed by 332 (68%). There was no significant overall difference concerning the four principal types of workplace: Clinical Chemistry, Blood Serology, Primary Care and Clinical Chemistry/Blood Serology. The main difference was found between those in managerial posts (N = 72) and the other MLTs (N = 260). Factor analysis showed three principal components, labelled Professionalism, Work Ethic, and Empathy, but also a different composition of variables of the components for the manager group compared with the non-manager group.