<SMALL>The development of complex information systems calls for <SPAN style='background:silver;'>conceptual</SPAN> <SPAN style='background:silver;'>models</SPAN> that describe aspects beyond entities and activities. In particular, recent research has pointed out that <SPAN style='background:silver;'>conceptual</SPAN> <SPAN style='background:silver;'>models</SPAN> need to model goals, in order to capture the intentions which underlie complex situations within an organisational context. This paper focuses on one class of goals, namely non-functional <SPAN style='background:silver;'>requirements</SPAN> (NFR), which need to be captured and analysed from the very early phases of the software development process. The paper presents a <SPAN style='background:silver;'>framework</SPAN> for <SPAN style='background:silver;'>integrating</SPAN> NFRs into the ER and OO <SPAN style='background:silver;'>models</SPAN>. This <SPAN style='background:silver;'>framework</SPAN> has been validated by two case studies, one of which is very large. The results of the case studies suggest that goal modelling during early phases can lead to a more productive and complete modelling activity.</SMALL>