Athletics at the 1986 Commonwealth Games – Men's 400 metres

Qualification: First 4 of each heat (Q) and the next 4 fastest (q) qualified for the semifinals.[2]

Rank	Heat	Name	Nationality	Time	Notes
1	2	Darren Clark	Australia	46.12	Q
2	1	Roger Black	England	46.66	Q
3	3	Brian Whittle	Scotland	46.69	Q
4	3	Phil Brown	England	46.78	Q
5	2	Kriss Akabusi	England	46.84	Q
6	1	Bruce Frayne	Australia	46.99	Q
7	3	David Johnston	Australia	47.13	Q
8	2	Andre Smith	Canada	47.21	Q
9	1	Anton Skerritt	Canada	47.53	Q
10	2	Martin Johnston	Scotland	48.19	Q
11	3	Michael Guegan	Jersey	48.40	Q
12	1	Joseph Rodan	Fiji	49.41	Q
13	3	Reuben Kaiaha Wotu	Vanuatu	49.44	q
14	2	Odiya Silweya	Malawi	49.45	q
15	3	Zacharia Machangani	Botswana	49.75	q
16	1	Brian Nicoll	Scotland	49.91	q
17	1	John Chappory	Gibraltar	50.65
18	2	Avelino Baldachino	Gibraltar	51.55
	1	Georges Taniel	Vanuatu	DNS

Qualification: First 4 of each semifinal qualified directly (Q) for the final.[3]

Rank	Heat	Name	Nationality	Time	Notes
1	2	Bruce Frayne	Australia	47.09	Q
2	1	Kriss Akabusi	England	47.15	Q
3	2	David Johnston	Australia	47.22	Q
4	2	Roger Black	England	47.27	Q
5	2	Brian Whittle	Scotland	47.56	Q
6	1	Darren Clark	Australia	47.61	Q
7	1	Phil Brown	England	47.72	Q
8	2	Anton Skerritt	Canada	47.74
9	1	Andre Smith	Canada	47.96	Q
10	1	Martin Johnston	Scotland	48.57
11	2	Michael Guegan	Jersey	48.80
12	2	Odiya Silweya	Malawi	49.56
13	1	Brian Nicoll	Scotland	50.07
14	2	Zacharia Machangani	Botswana	50.09
15	1	Joseph Rodan	Fiji	50.30
16	1	Reuben Kaiaha Wotu	Vanuatu	51.08