Warren Spahn has won the most career games by a 40-year-old pitcher, with 22 wins.

Interpreted as:

most regular-season wins by a player over age of 40

	NAME	W	L	W%	G	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Warren Spahn W. Spahn	22	14	.611	40	36	3.27	123	21	4	0	272.1	256	99	108	26	68	3	3	3	1,116	3	4.06	2.25	1.81	0.86	11.0	6.1	1.19	.257	3.57	8.46
2	Jamie Moyer J. Moyer	21	7	.750	33	33	3.27	129	1	0	0	215.0	199	78	83	19	66	8	0	3	897	0	5.40	2.76	1.95	0.80	14.4	7.4	1.23	.267	3.47	8.33
3	Phil Niekro P. Niekro	21	20	.512	44	44	3.39	208	23	1	0	342.0	311	129	160	41	113	11	0	8	1,436	18	5.47	2.97	1.84	1.08	14.5	7.9	1.24	.254	4.21	8.18
4	Grover Alexander G. Alexander	21	10	.677	37	30	2.52	48	22	2	3	268.0	261	75	94	11	38	1	5		1,082	1	1.61	1.28	1.26	0.37	4.4	3.5	1.12	.254	3.16	8.76
5	Eddie Plank E. Plank	18	16	.529	42	27	2.53	109	16	4	3	249.0	215	70	91	3	61	6	13			4	3.94	2.20	1.79	0.11		7.2	1.11	.318	3.29	7.77
6	Bartolo Colon B. Colon	17	9	.654	30	30	2.98	130	2	2	0	193.1	208	64	69	16	31	2	0	0	802	1	6.05	1.44	4.19	0.74	16.2	3.9	1.24	.308	3.21	9.68
7	Tom Seaver T. Seaver	16	11	.593	35	33	3.17	134	6	1	0	238.2	223	84	103	22	69	8	0	6	993	10	5.05	2.60	1.94	0.83	13.5	6.9	1.22	.264	3.88	8.41
8	Tom Glavine T. Glavine	15	7	.682	32	32	3.82	131	0	0	0	198.0	202	84	94	22	62	6	0	7	842	1	5.95	2.82	2.11	1.00	15.6	7.4	1.33	.290	4.27	9.18
9	Roger Clemens R. Clemens	15	10	.600	32	32	4.13	210	1	1	0	205.0	199	94	101	24	60	7	0	3	866	13	9.22	2.63	3.50	1.05	24.2	6.9	1.26	.310	4.43	8.74
10	Orel Hershiser O. Hershiser	15	10	.600	32	32	4.44	96	0	0	0	184.2	183	91	93	14	81	9	0	3	802	7	4.68	3.95	1.19	0.68	12.0	10.1	1.43	.281	4.53	8.92
11	Charlie Hough C. Hough	15	16	.484	34	34	3.32	174	10	0	0	252.0	202	93	111	20	126	12	0	1	1,067	10	6.21	4.50	1.38	0.71	16.3	11.8	1.30	.248	3.96	7.21
12	Don Sutton D. Sutton	15	10	.600	34	34	3.86	107	1	1	0	226.0	221	97	101	25	59	0	0	0	943	6	4.26	2.35	1.81	1.00	11.3	6.3	1.24	.261	4.02	8.80
13	Gaylord Perry G. Perry	15	11	.577	36	36	2.80	165	11	0	0	266.1	248	83	95	12	70	4	0	10	1,086	6	5.58	2.37	2.36	0.41	15.2	6.4	1.19	.283	3.21	8.38
14	Jack Quinn J. Quinn	15	17	.469	46	31	3.89	74	18	2	10	259.0	301	112	137	11	58	12	13		1,120	3	2.57	2.02	1.28	0.38	6.6	5.2	1.39	.301	4.76	10.46
15	Greg Maddux G. Maddux	14	15	.483	34	34	4.31	119	0	0	0	209.0	223	100	111	20	34	1	0	7	862	1	5.12	1.46	3.50	0.86	13.8	3.9	1.23	.295	4.78	9.60
16	Kenny Rogers K. Rogers	14	8	.636	30	30	3.46	87	1	1	0	195.1	205	75	86	15	53	8	0	1	828	0	4.01	2.44	1.64	0.69	10.5	6.4	1.32	.286	3.96	9.45
17	Randy Johnson R. Johnson	14	13	.519	33	33	2.70	275	5	3	0	229.2	163	69	79	18	43	10	0	1	898	3	10.78	1.69	6.40	0.71	30.6	4.8	0.90	.263	3.10	6.39
18	Dennis Martinez D. Martinez	14	7	.667	32	32	3.65	105	3	2	0	209.1	194	85	92	23	58	10	0	2	866	3	4.51	2.49	1.81	0.99	12.1	6.7	1.20	.255	3.96	8.34
19	Justin Verlander J. Verlander	13	8	.619	27	27	3.22	144	0	0	0	162.1	139	58	63	18	45	5	0	0	669	5	7.98	2.49	3.20	1.00	21.5	6.7	1.13	.265	3.49	7.71
20	Adam Wainwright A. Wainwright	13	9	.591	32	32	3.16	149	1	0	0	199.2	181	70	72	18	53	6	0	1	814	6	6.72	2.39	2.81	0.81	18.3	6.5	1.17	.277	3.25	8.16
21	Woody Williams W. Williams	13	13	.500	35	34	4.62	99	0	0	0	206.1	226	106	115	37	52	11	0	5	895	2	4.32	2.27	1.90	1.61	11.1	5.8	1.35	.272	5.02	9.86
22	Rick Reuschel R. Reuschel	13	10	.565	31	31	3.54	107	2	0	0	203.2	196	80	86	18	57	1	0	10	857	2	4.73	2.52	1.88	0.80	12.5	6.7	1.24	.264	3.80	8.66
23	Early Wynn E. Wynn	13	12	.520	36	34	3.45	158	12	4	1	237.1	220	91	105	20	112	4	2	2	1,025	1	5.99	4.25	1.41	0.76	15.4	10.9	1.40	.274	3.98	8.34
24	Clarence Mitchell C. Mitchell	13	11	.542	27	25	4.07	39	13	0	0	190.1	221	86	103	10	52	3	1		839	1	1.84	2.46	0.75	0.47	4.6	6.2	1.43	.287	4.87	10.45
25	Red Faber R. Faber	13	13	.500	31	31	3.62	72	15	1	0	246.0	254	99	119	10	58	9	0		1,035	4	2.63	2.12	1.24	0.37	7.0	5.6	1.27	.275	4.35	9.29