With economic globalization and with the precarization and informalization of work, efforts have increased to build global labour alliances among formal workers on the one hand and to organize informal workers on the other. These two endeavours overlap considerably. Global labour organizations have taken on a growing role in organizing and advocating for informal workers. I explore this overlap by comparing two global labour federations: one arising from heterogeneous networks of informal workers--the International Domestic Workers Federation (IDWF)--and a longstanding one of formal employees that has increasingly attempted to include informal workers --the Building and Wood Workers International (BWI). For both cases, I draw on five sources: secondary literature; archival material from the two federations; seven semi-structured interviews with experts on and members of these federations, plus a meeting with a small group of BWI leaders; and observations of several IDWF and BWI events. This comparison yields two striking findings. First, despite contrasting environments and historical legacies, the two federations show much convergence in strategy. Second, they clearly differ in their degree of adherence to the standard trade union model, as a result of differences in assets and challenges. The BWI is strongly wedded to the conventional model and struggles to reach informal workers, while enjoying a robust inflow of membership dues. The IDWF is committed to welcoming a variety of organizations and readily mobilizes informal workers, while suffering from an anemic inflow of membership dues. These challenges must be met not just for the survival of the BWI and the IDWF but also for the prospect of organizing globally to defend informal and precarious workers. With economic globalization and with the precarization and informalization of work, efforts have increased to build global labour alliances among formal workers on the one hand and to organize informal workers on the other. These two endeavours overlap considerably. Global labor organizations have taken on a growing role in organizing and advocating for informal workers. I explore this overlap by comparing two global labour federations: one arising from heterogeneous networks of informal workers--the International Domestic Workers Federation--and a longstanding one of formal employees that has increasingly attempted to include informal workers --the Building and Wood Workers International. The contrast reveals similarities, divergences and trade-offs, with important implications for the future potential for building global organizations of informal workers. Keywords: Construction workers; domestic workers; global unions; informal work; power resources Avec la mondialisation economique et la hausse du precariat, les efforts se sont multiplies pour creer des alliances mondiales entre les travailleurs formels, d'une part, et pour organiser les travailleurs informels, d'autre part. Ces deux efforts se chevauchent considerablement. Les organisations syndicales internationales jouent un role de plus en plus important dans l'organisation et la defense des travailleurs informels. J'explore ce chevauchement en comparant deux federations syndicales mondiales: l'une issue de reseaux heterogenes de travailleurs informels--the International Domestic Workers Federation (IDWF)--et l'autre, creee de longue date par des employes formels, qui tente de plus en plus d'inclure les travailleurs informels--the Building and Wood Workers International (BWI). Dans les deux cas, je m'appuie sur cinq sources: la litterature secondaire, les archives des deux federations, sept entretiens semi diriges avec des experts et des membres de ces federations, ainsi qu'une reunion avec un petit groupe de dirigeants de l'IBB, et l'observation de plusieurs evenements organises par l'IDWF et le BWI. Cette comparaison permet de faire deux constatations frappantes. Tout d'abord, malgre des environnements et des heritages historiques contrastes, les deux federations presentent une grande convergence de strategie. Deuxiemement, elles different clairement dans leur degre d'adhesion au modele syndical standard, en raison de differences d'atouts et de defis. Le BWI est fortement attachee au modele conventionnel et lutte pour atteindre les travailleurs informels, tout en beneficiant d'un afflux important de cotisations. L'IDWF s'est engagee a accueillir une variete d'organisations et mobilise facilement les travailleurs informels, tout en souffrant d'un afflux anemique de cotisations. Ces defis doivent etre releves non seulement pour la survie du BWI et de l'IDWF, mais aussi pour la perspective de la defense des travailleurs informels et precaires au niveau mondial., 1. Introduction Labour scholars and practitioners alike have been showing much interest in two trends of the world of work: economic globalization (Bercusson & Estlund, 2008; Brookes & McCallum, 2017); [...]