most wins in a season by a pitcher without a loss since 1945

Since 1945, Denny McLain has the most wins in wins in a season, with 31 wins in 1968.

	NAME	W	L	SEASON	TM	W%	L%	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	Denny McLain D. McLain	31	0	1968	DET	1.000	.000	35	35	1.70	259	28	6	0	302.0	209	57	62	24	52	5	0	1	1,145	3	7.72	1.55	4.98	0.72	22.6	4.5	0.86	.230	1.85	6.23
2	Robin Roberts R. Roberts	28	0	1952	PHN	1.000	.000	32	30	2.42	127	27	3	2	279.0	242	75	82	17	39	3	2		1,102	1	4.10	1.26	3.26	0.55	11.5	3.5	1.01	.246	2.65	7.81
3	Bob Welch B. Welch	27	0	1990	OAK	1.000	.000	29	29	2.18	114	2	2	0	206.2	175	50	61	20	62	4	0	2	835	2	4.96	2.70	1.84	0.87	13.7	7.4	1.15	.244	2.66	7.62
4	Steve Carlton S. Carlton	27	0	1972	PHI	1.000	.000	31	31	1.44	235	24	8	0	268.0	189	43	48	11	57	1	0	4	1,023	7	7.89	1.91	4.12	0.37	23.0	5.6	0.92	.248	1.61	6.35
5	Sandy Koufax S. Koufax	27	0	1966	LAD	1.000	.000	32	32	1.26	268	24	5	0	263.1	192	37	46	11	60	0	0	3	1,030	6	9.16	2.05	4.47	0.38	26.0	5.8	0.96	.262	1.57	6.56
6	Don Newcombe D. Newcombe	27	0	1956	BKN	1.000	.000	31	29	2.59	113	16	5	0	229.1	176	66	71	24	33	1	2	5	881	2	4.43	1.30	3.42	0.94	12.8	3.7	0.91	.214	2.79	6.91
7	Juan Marichal J. Marichal	26	0	1968	SFG	1.000	.000	29	29	1.82	177	24	5	0	256.2	206	52	63	13	34	4	0	3	998	7	6.21	1.19	5.21	0.46	17.7	3.4	0.94	.251	2.21	7.22
8	Sandy Koufax S. Koufax	26	0	1965	LAD	1.000	.000	35	33	1.73	325	25	8	2	275.0	170	53	64	20	55	3	2	2	1,050	9	10.64	1.80	5.91	0.65	31.0	5.2	0.82	.232	2.09	5.56
9	Bob Feller B. Feller	26	0	1946	CLE	1.000	.000	33	27	1.23	248	26	10	4	256.0	163	35	35	6	99	2	5		1,007	3	8.72	3.48	2.51	0.21	24.6	9.8	1.02	.241	1.23	5.73
10	Hal Newhouser H. Newhouser	26	0	1946	DET	1.000	.000	28	26	1.26	218	25	6	1	235.2	149	33	41	3	72	0	2		920	5	8.33	2.75	3.03	0.11	23.7	7.8	0.94	.233	1.57	5.69
11	Steve Stone S. Stone	25	0	1980	BAL	1.000	.000	30	30	2.62	128	8	1	0	216.2	176	63	68	17	83	6	0	2	882	6	5.32	3.45	1.54	0.71	14.5	9.4	1.20	.245	2.82	7.31
12	Ron Guidry R. Guidry	25	0	1978	NYY	1.000	.000	32	32	1.54	234	15	9	0	257.0	168	44	49	10	71	1	0	1	988	7	8.19	2.49	3.30	0.35	23.7	7.2	0.93	.235	1.72	5.88
13	Fergie Jenkins F. Jenkins	25	0	1974	TEX	1.000	.000	29	29	1.68	180	22	6	0	236.1	185	44	54	11	27	4	0	2	915	3	6.85	1.03	6.67	0.42	19.7	3.0	0.90	.251	2.06	7.05
14	Catfish Hunter C. Hunter	25	0	1974	OAK	1.000	.000	29	29	1.69	106	16	6	0	228.2	172	43	48	15	27	2	0	0	868	0	4.17	1.06	3.93	0.59	12.2	3.1	0.87	.219	1.89	6.77
15	Mickey Lolich M. Lolich	25	0	1971	DET	1.000	.000	31	31	2.13	224	22	4	0	270.1	220	64	74	20	64	4	0	2	1,081	5	7.46	2.13	3.50	0.67	20.7	5.9	1.05	.260	2.46	7.32
16	Tom Seaver T. Seaver	25	0	1969	NYM	1.000	.000	29	28	1.77	180	17	5	0	234.1	161	46	53	17	71	6	1	9	923	6	6.91	2.73	2.54	0.65	19.5	7.7	0.99	.222	2.04	6.18
17	Jim Kaat J. Kaat	25	0	1966	MIN	1.000	.000	28	28	2.16	160	19	3	0	237.0	193	57	62	19	39	2	0	4	926	9	6.08	1.48	4.10	0.72	17.3	4.2	0.98	.246	2.35	7.33
18	Juan Marichal J. Marichal	25	0	1966	SFG	1.000	.000	31	30	1.77	190	23	4	0	264.1	184	52	62	26	26	1	1	2	993	3	6.47	0.89	7.31	0.89	19.1	2.6	0.79	.211	2.11	6.26
19	Sandy Koufax S. Koufax	25	0	1963	LAD	1.000	.000	35	35	1.44	275	20	11	0	287.0	183	46	48	14	51	3	0	6	1,099	3	8.62	1.60	5.39	0.44	25.0	4.6	0.82	.224	1.51	5.74
20	Juan Marichal J. Marichal	25	0	1963	SFG	1.000	.000	33	32	2.13	210	17	5	0	266.1	202	63	78	21	52	2	1	2	1,046	2	7.10	1.76	4.04	0.71	20.1	5.0	0.95	.238	2.64	6.83
21	Don Drysdale D. Drysdale	25	0	1962	LAD	1.000	.000	34	33	2.38	193	19	2	1	268.1	218	71	84	16	57	7	1	8	1,072	7	6.47	1.91	3.39	0.54	18.0	5.3	1.02	.253	2.82	7.31
22	Whitey Ford W. Ford	25	0	1961	NYY	1.000	.000	35	35	3.27	189	11	3	0	255.2	218	93	100	21	78	1	0	3	1,042	8	6.65	2.75	2.42	0.74	18.1	7.5	1.16	.262	3.52	7.67
23	Mel Parnell M. Parnell	25	0	1949	BSA	1.000	.000	32	27	1.99	108	23	4	2	244.2	196	54	64	5	95	3	4		992	4	3.97	3.49	1.14	0.18	10.9	9.6	1.19	.245	2.35	7.21
24	Dave Ferriss D. Ferriss	25	0	1946	BSA	1.000	.000	34	29	3.13	94	22	6	3	238.1	228	83	87	11	60	3	4		979	0	3.55	2.27	1.57	0.42	9.6	6.1	1.21	.268	3.29	8.61
25	Hal Newhouser H. Newhouser	25	0	1945	DET	1.000	.000	31	27	1.28	164	24	8	2	245.1	171	35	40	3	74	0	2		955	9	6.02	2.71	2.22	0.11	17.2	7.7	1.00	.235	1.47	6.27