Stephen Silas has the worst record by a coach when playing 200+ games, with a record of 59-177.

worst nba coaching record with at least 200 games

COACH	GP	REC	W%	MPG	PPG	RPG	APG	SPG	BPG	TPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	MIN	PTS	REB	AST	STL	BLK	TOV	PF
Stephen Silas	236	59-177	.250	240.7	109.8	43.7	23.2	7.4	4.7	15.2	39.8	87.9	45.2	12.5	36.9	33.9	17.8	24.1	73.6	56,815	25,911	10,308	5,466	1,746	1,117	3,576	4,778
Sidney Lowe	307	79-228	.257	241.1	93.7	40.2	23.1	7.7	5.3	16.1	35.7	79.7	44.9	3.2	10.0	32.1	19.1	25.1	76.0	74,005	28,776	12,348	7,104	2,350	1,616	4,947	6,802
Tim Floyd	321	90-231	.280	241.6	86.7	40.5	21.0	8.3	4.3	15.2	32.4	77.8	41.6	4.5	14.0	32.1	17.5	24.1	72.6	77,565	27,836	13,009	6,736	2,660	1,373	4,877	7,129
Kurt Rambis	229	65-164	.284	241.0	99.3	43.4	20.3	7.1	4.7	15.5	37.6	83.7	44.9	6.1	16.8	36.2	18.1	24.2	74.6	55,185	22,739	9,941	4,658	1,625	1,068	3,543	4,921
Ron Rothstein	328	97-231	.296	241.3	100.2	43.3	23.7	8.6	4.4	17.7	40.1	87.8	45.6	1.9	6.0	31.3	18.1	25.6	70.8	79,145	32,864	14,217	7,759	2,818	1,432	5,807	8,074
Eddie Donovan	278	84-194	.302	241.3	111.9						43.9						24.1	34.3	70.2	67,095	31,121
Bill Musselman	258	78-180	.302	242.0	100.1	41.4	23.1				40.1	88.4	45.4	0.9			18.9	25.1	75.3	62,445	25,834	10,675	5,963				6,069
Johnny Kerr	283	93-190	.329	241.4	112.4						43.4	100.7	43.1				25.5	35.2	72.6	68,320	31,807						7,402
Chauncey Billups	246	81-165	.329	241.2	108.7	42.1	23.4	7.5	4.5	13.9	39.5	87.4	45.1	12.3	35.1	35.2	17.4	22.2	78.3	59,340	26,732	10,345	5,755	1,837	1,096	3,424	5,025
Johnny Davis	219	73-146	.333	241.0	98.2	43.1	19.8	7.6	4.6	15.2	36.3	82.4	44.1	4.9	14.6	33.6	20.6	27.7	74.4	52,785	21,502	9,428	4,344	1,657	999	3,325	4,753
George Irvine	290	100-190	.345	241.2	102.9	45.5	23.2	7.7	4.8	17.6	39.9	86.2	46.3	2.1	6.6	32.4	20.9	28.2	74.2	69,950	29,843	13,189	6,725	2,225	1,387	5,097	7,513
Richie Adubato	367	127-240	.346	241.3	101.2						39.7			2.7			19.1	25.4	75.2	88,555	37,147						8,475
David Fizdale	205	71-134	.346	241.6	102.0	43.4	20.6	7.4	4.8	13.2	37.1	85.5	43.4	9.8	28.2	34.6	18.1	23.7	76.2	49,525	20,902	8,898	4,220	1,526	977	2,697	4,503
Jay Triano	308	108-200	.351	241.0	101.8	41.5	21.9	6.5	4.5	13.7	38.5	83.1	46.3	6.4	18.5	34.5	18.5	24.1	76.7	74,220	31,346	12,772	6,741	2,011	1,385	4,222	6,637
Keith Smart	263	93-170	.354	241.6	100.0	41.9	21.4	8.4	5.0	14.6	38.2	85.2	44.8	6.9	19.2	35.8	16.8	22.0	76.1	63,545	26,311	11,028	5,637	2,206	1,304	3,843	5,571
Johnny Bach	267	95-172	.356	241.8	110.7	43.3	23.1	9.6	4.0	17.6	43.4	92.0	47.2	1.0	3.5	28.5	22.9	30.4	75.5	64,555	29,563	11,568	6,169	2,570	1,071	4,693	6,830
Dave DeBusschere	222	79-143	.356	241.1	110.4						43.6						23.2	33.1	70.0	53,530	24,517
Don Casey	238	85-153	.357	241.5	101.3	41.8	22.9	9.4	5.5	15.9	38.9	85.0	45.7	3.0	9.2	33.2	20.6	27.2	75.7	57,470	24,118	9,939	5,461	2,242	1,318	3,773	5,384
Jacque Vaughn	355	129-226	.363	241.4	102.6	42.1	23.4	7.1	4.7	13.5	39.0	84.8	46.0	9.3	25.6	36.2	15.3	20.0	76.5	85,700	36,412	14,957	8,296	2,509	1,663	4,795	7,203
Wes Unseld	547	202-345	.369	241.7	103.9	42.5	24.8	8.1	4.9	15.6	41.4	88.5	46.8	1.3	4.9	26.2	19.8	26.0	75.9	132,205	56,819	23,234	13,570	4,407	2,657	8,512	12,520
Wes Unseld Jr.	207	77-130	.372	241.1	111.8	42.7	25.8	6.8	5.1	13.1	41.7	87.4	47.8	11.2	31.9	35.0	17.1	21.9	78.1	49,905	23,139	8,841	5,334	1,411	1,062	2,708	3,945
Scotty Robertson	287	109-178	.380	241.7	107.3	44.0					42.3	89.4	47.3	0.6			22.2	30.0	74.0	69,355	30,787	12,630					7,433
Garry St. Jean	450	172-278	.382	241.4	100.0	42.3	23.2	8.3	4.7	16.3	37.7	83.1	45.4	4.2	11.8	35.6	20.4	28.0	72.7	108,625	45,004	19,027	10,437	3,719	2,135	7,326	11,185
Andrew Levane	277	106-170	.383	242.2	96.6						35.2						26.1	35.3	74.0	67,080	26,746
Kenny Atkinson	307	118-189	.384	242.4	108.7	45.7	23.2	6.6	4.5	14.8	39.0	87.9	44.4	12.2	35.2	34.8	18.4	24.1	76.3	74,430	33,385	14,015	7,124	2,040	1,395	4,543	6,438