How valuable is policy advice and lobbying in parliamentary decision-making, and which associated values occur most relevant for democracy? Undoubtedly, politicians are expected to undertake informed decisions, to balance different views and interests, and eventually, to act in the name of public good. At the same time, they might be vulnerable to pressure of their constituencies, the official political party line, lobbies, or simply, have limited access to specific knowledge. This exploratory research aims to identify which ethical values, associated to lobbying and policy advice (PA), occur relevant for MPs while undertaking meaningful decisions. Which values are important for lobbyists and policy advisors? What does transparency, integrity, responsibility, trust in lobbying and policy advising mean for them? How these values are defined and interpreted by politicians, lobbyists, policy advisors? What is their significance under the conditions of backsliding and consolidated democracy? We rely on over one hundred in-depth semi-structured interviews with MPs and experts from Poland and Germany involved in parliamentary policy-making. We expect to identify different values specific for lobbying and for policy advice. Also, although some values seem to be universal, we expect to find different prevailing values related to lobbying and to policy advice in both countries. With this comparative research we seek to contribute to the literature on the role of policy advice and lobbying in democracies, and more specifically, to generate arguments on how the identified values reflect the quality of democracy.