The informative section of AWS B4.0-Annex D offers a recommended practice for all-weld-metal tensile testing of narrow groove pipeline girth welds, sampling a higher proportion of weld metal than is possible with more traditional testing practices. An interlaboratory study (ILS) program was conducted to examine the applicability and practicability of AWS B4.0-Annex D. Program participants represented a broad range of interests across industry, government, and academia. Precision statistics of the test method were assessed according to ASTM E691 and E177. This paper includes results of the assessments. The results from the ILS demonstrate that AWS B4.0-Annex D is repeatable and reproducible for determination of tensile properties of narrow groove pipeline girth welds.