lowest era by a starting pitcher since 1920 with at least 20 games started in a single season

Since 1920, Bob Gibson has the best ERA by a starting pitcher with 20+ starts in a season, with an ERA of 1.12 in 1968.

	NAME	ERA	GS	SEASON	TM	G	W	L	W%	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	Bob Gibson B. Gibson	1.12	34	1968	STL	34	22	9	.710	268	28	13	0	304.2	198	38	49	11	62	7	0	6	1,161	4	7.92	1.83	4.32	0.32	23.1	5.3	0.85	.230	1.45	5.85
2	Dwight Gooden D. Gooden	1.53	35	1985	NYM	35	24	4	.857	268	16	8	0	276.2	198	47	51	13	69	2	0	4	1,065	6	8.72	2.24	3.88	0.42	25.2	6.5	0.97	.259	1.66	6.44
3	Greg Maddux G. Maddux	1.56	25	1994	ATL	25	16	6	.727	156	10	3	0	202.0	150	35	44	4	31	6	0	3	774	3	6.95	1.38	5.03	0.18	20.2	4.0	0.90	.253	1.96	6.68
4	Luis Tiant L. Tiant	1.57	32	1968	CLE	32	21	8	.724	256	19	9	0	253.0	143	44	51	15	70	4	0	3	960	3	9.11	2.49	3.66	0.53	26.7	7.3	0.84	.208	1.81	5.09
5	Dean Chance D. Chance	1.57	35	1964	LAA	35	18	8	.692	190	15	11	0	257.1	180	45	48	7	78	2	0	8	1,009	8	6.65	2.73	2.44	0.24	18.8	7.7	1.00	.236	1.68	6.30
6	Greg Maddux G. Maddux	1.63	28	1995	ATL	28	19	2	.905	181	10	3	0	209.2	147	38	39	8	23	4	0	3	785	1	7.77	0.99	7.87	0.34	23.1	2.9	0.81	.244	1.67	6.31
7	Spud Chandler S. Chandler	1.64	30	1943	NYY	30	20	4	.833	134	20	5	0	253.0	197	46	62	5	54	4	0		988	3	4.77	1.92	2.48	0.18	13.6	5.5	0.99	.243	2.21	7.01
8	Zack Greinke Z. Greinke	1.66	32	2015	LAD	32	19	3	.864	200	1	0	0	222.2	148	41	43	14	40	5	0	1	843	7	8.08	1.62	5.00	0.57	23.7	4.7	0.84	.229	1.74	5.98
9	Clayton Kershaw C. Kershaw	1.69	21	2016	LAD	21	12	4	.750	172	3	3	0	149.0	97	28	31	8	11	2	0	1	544	5	10.39	0.66	15.64	0.48	31.6	2.0	0.72	.254	1.87	5.86
10	Nolan Ryan N. Ryan	1.69	21	1981	HOU	21	11	5	.688	140	5	3	0	149.0	99	28	34	2	68	1	0	1	605	16	8.46	4.11	2.06	0.12	23.1	11.2	1.12	.246	2.05	5.98
11	Jacob deGrom J. deGrom	1.70	32	2018	NYM	32	10	9	.526	269	1	0	0	217.0	152	41	48	10	46	5	0	3	835	2	11.16	1.91	5.85	0.41	32.2	5.5	0.91	.281	1.99	6.30
12	Tom Seaver T. Seaver	1.70	35	1971	NYM	35	20	9	.690	288	21	4	0	285.2	207	54	59	17	61	4	0	2	1,098	4	9.07	1.92	4.72	0.54	26.2	5.6	0.94	.261	1.86	6.52
13	Sandy Koufax S. Koufax	1.73	41	1966	LAD	41	27	9	.750	317	27	5	0	323.0	241	62	74	19	77	0	0	4	1,274	7	8.83	2.15	4.12	0.53	24.9	6.0	0.98	.258	2.06	6.72
14	Mort Cooper M. Cooper	1.73	35	1942	SLN	35	22	6	.786	151	22	10	0	276.0	203	53	71	8	67	5	0		1,086	5	4.92	2.18	2.25	0.26	13.9	6.2	0.98	.228	2.32	6.62
15	Pedro Martinez P. Martinez	1.74	29	2000	BOS	29	18	6	.750	284	7	4	0	217.0	128	42	44	17	32	14	0	0	817	1	11.78	1.33	8.88	0.71	34.8	3.9	0.74	.236	1.82	5.31
16	Ron Guidry R. Guidry	1.74	35	1978	NYY	35	25	3	.893	248	16	9	0	273.2	187	53	61	13	72	1	0	1	1,057	7	8.16	2.37	3.44	0.43	23.5	6.8	0.95	.241	2.01	6.15
17	Justin Verlander J. Verlander	1.75	28	2022	HOU	28	18	4	.818	185	0	0	0	175.0	116	34	43	12	29	6	0	0	666	3	9.51	1.49	6.38	0.62	27.8	4.4	0.83	.240	2.21	5.97
18	Hal Newhouser H. Newhouser	1.75	36	1945	DET	36	24	9	.727	207	29	8	0	308.1	234	60	70	5	106	0	0		1,237	9	6.04	3.09	1.95	0.15	16.7	8.6	1.10	.249	2.04	6.83
19	Sandy Koufax S. Koufax	1.76	28	1964	LAD	28	19	5	.792	221	15	7	0	220.0	153	43	49	13	53	0	0	5	860	9	9.04	2.17	4.17	0.53	25.7	6.2	0.94	.244	2.00	6.26
20	Jake Arrieta J. Arrieta	1.77	33	2015	CHC	33	22	6	.786	236	4	3	0	229.0	150	45	52	10	48	6	0	2	870	6	9.28	1.89	4.92	0.39	27.1	5.5	0.86	.246	2.04	5.90
21	Clayton Kershaw C. Kershaw	1.77	27	2014	LAD	27	21	3	.875	239	6	2	0	198.1	139	39	42	9	31	2	0	0	749	7	10.85	1.41	7.71	0.41	31.9	4.1	0.86	.278	1.91	6.31
22	Carl Hubbell C. Hubbell	1.77	33	1933	NYG	33	20	11	.645	139	22	10	0	274.0	231	54	66	6	42	3	0		1,074	3	4.57	1.38	3.31	0.20	12.9	3.9	1.00	.255	2.17	7.59
23	Vida Blue V. Blue	1.82	39	1971	OAK	39	24	8	.750	301	24	8	0	312.0	209	63	73	19	88	4	0	3	1,207	10	8.68	2.54	3.42	0.55	24.9	7.3	0.95	.239	2.11	6.03
24	Sam McDowell S. McDowell	1.82	37	1968	CLE	37	15	14	.517	281	11	3	0	267.0	180	54	78	13	109	10	0	9	1,091	7	9.47	3.67	2.58	0.44	25.8	10.0	1.08	.246	2.63	6.07
25	Joe Horlen J. Horlen	1.83	28	1964	CWS	28	12	9	.571	134	9	2	0	201.2	130	41	50	10	52	4	0	4	776	3	5.98	2.32	2.58	0.45	17.3	6.7	0.90	.208	2.23	5.80