Tanzania Journal of Agricultural Sciences 1999, Vol. 2(2: pp 171-180Raillwater h.{pvesting (RWH) ,shuuld"be 'regarded as a continuum of techniques thill' link in-situ soil-wate!: conservation at on~'exi;-'ellle to co'nventiona!irrigation {it the ·other. bHitu KWH, comprises i~ group of techniques for preventing runoff and promoting infiltration: Mic/'()-catc~mellt RWH comprises'a group'oftechniques/or collecting overlandfZow;(sheetor rill) from a catchment area and delivering it to a cropped.area in order to supplement the inadequate direc·t':air!faZ{ The transfer nomllllly occurs ·over a reJativelyshOit distance entirely withirt the land-holding of an individual farmer and the system is therefore sometimes known as 'an "illtemai cauhment" .. Macro-catchment RWH comprises a group' of techniques in which natural runoff is collected Fum a relatively large area .and. tr(1nsferred over.a longer distance. Examples of each pf these categories of RWH exist' ill p'a,t's 0/ Ta,';iania, but their potential is }eirgely neglected, by research and extension"seivices alzd they are illlder-exploited. The pUipose of this paper was to 'assess the extent to which thediflerent rainwater harvesting systeniS, are used in Tanzania. The findings show that there is a widespread practice of rainwater harvesting in Tanzania. Rainwater hmvestillg with storage of wate!' for livestock has received govemment SUppOit in the past . . However, rruzny storage reselvoir~ have been destroyed by siltation. On the other hand rainwater hmvesting for crop production has llOt received an adequate SUppOit from research and extension services. Therefore, although farmers are practiciizg rainwaterhmvesting, they are faced with sh01tage of appropriate technolo giesand know