Albeit their nature remains elusive, relativistic, collimated outflows of energy and particles appear to be a nearly ubiquitous feature of accreting black holes. As evidence accumulates for a dominant role of the jet in dissipating the liberated accretion power, questions around their powering mechanism and even composition remain unanswered. In this chapter, I will describe the main observational properties of relativistic jets from black hole X-ray binaries, with a particular emphasis on recent developments around three main topics: (i) the role and relative importance of the accretion flow, relativistic jet and equatorial wind; (ii) the existence of global luminosity-luminosity correlation(s) in quiescent and hard state black hole X-ray binaries, and their interpretation(s); (iii) (ways of estimating) the total jet power, and its relation to black hole spin.