Since 1900, the Chicago Whales have the best ERA by a team, with an ERA of 2.54.

	TEAM	ERA	G	W%	W	L	GS	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Whales	2.54	312	.565	173	133	312	1,226	190	35	18	2818.0	2,436	795	1,055	77	795	66		11,176	59	3.92	2.54	1.54	0.25	11.0	7.1	1.15	.262	3.37	7.78
2	Peppers	2.83	312	.551	168	137	312	1,245	204	31	16	2804.1	2,660	882	1,184	44	929	102		11,450	63	4.00	2.98	1.34	0.14	10.9	8.1	1.28	.287	3.80	8.54
3	Packers	3.11	307	.487	148	156	307	1,126	177	25	23	2720.0	2,597	941	1,234	66	835	83		11,102	74	3.73	2.76	1.35	0.22	10.1	7.5	1.26	.281	4.08	8.59
4	Terriers	3.15	313	.489	149	156	313	1,359	191	33	15	2793.2	2,685	978	1,225	60	805	71		11,396	60	4.38	2.59	1.69	0.19	11.9	7.1	1.25	.288	3.95	8.65
5	Rebels	3.18	310	.495	150	153	310	1,027	185	25	18	2752.1	2,689	971	1,222	74	885	53		11,152	44	3.36	2.89	1.16	0.24	9.2	7.9	1.30	.287	4.00	8.79
6	Blues	3.27	308	.508	154	149	308	1,256	168	25	27	2747.0	2,520	998	1,236	80	1,058	76		11,249	65	4.12	3.47	1.19	0.26	11.2	9.4	1.30	.278	4.05	8.26
7	Tip-Tops	3.35	310	.480	147	159	310	1,103	169	20	25	2741.0	2,674	1,020	1,350	58	1,095	76		11,416	70	3.62	3.60	1.01	0.19	9.7	9.6	1.38	.288	4.43	8.78
8	Dodgers	3.49	19,627	.532	10,393	9,139	19,627	108,198	6,009	1,174	3,337	176024.0	167,080	68,313	79,857	12,807	60,082	4,665	3,451	741,545	4,728	5.53	3.07	1.80	0.65	14.6	8.1	1.29	.278	4.08	8.54
9	Terrapins	3.54	314	.425	131	177	314	1,302	173	20	20	2752.1	2,844	1,082	1,388	86	858	78		11,244	61	4.26	2.81	1.52	0.28	11.6	7.6	1.35	.309	4.54	9.30
10	Giants	3.61	19,625	.533	10,408	9,124	19,625	100,471	5,682	1,020	3,427	175608.0	170,934	70,365	81,767	13,609	59,274	4,368	3,857	743,966	4,784	5.15	3.04	1.70	0.70	13.5	8.0	1.31	.278	4.19	8.76
11	Yankees	3.66	19,176	.570	10,872	8,216	19,176	101,342	5,871	998	3,667	171420.0	164,912	69,656	80,008	13,427	61,030	4,431	2,271	724,472	4,576	5.32	3.20	1.66	0.70	14.0	8.4	1.32	.278	4.20	8.66
12	Cardinals	3.68	19,636	.521	10,183	9,347	19,636	96,518	5,857	996	3,335	175694.0	173,936	71,889	83,586	12,878	60,362	4,826	3,599	746,373	4,654	4.94	3.09	1.60	0.66	12.9	8.1	1.33	.282	4.28	8.91
13	Braves	3.73	19,613	.491	9,570	9,932	19,613	96,533	6,159	949	3,026	175336.0	174,200	72,689	84,522	13,030	61,205	4,325	3,805	745,751	4,718	4.96	3.14	1.58	0.67	12.9	8.2	1.34	.282	4.34	8.94
14	Pirates	3.74	19,622	.504	9,843	9,683	19,622	94,666	5,749	979	3,156	175209.0	175,134	72,808	84,309	12,740	59,049	4,935	3,957	745,603	4,709	4.86	3.03	1.60	0.65	12.7	7.9	1.34	.283	4.33	9.00
15	Cubs	3.74	19,649	.505	9,864	9,678	19,649	103,078	5,764	1,015	3,118	175744.2	172,997	73,102	84,619	13,925	62,124	4,746	3,749	748,767	4,859	5.28	3.18	1.66	0.71	13.8	8.3	1.34	.282	4.33	8.86
16	Reds	3.79	19,644	.498	9,739	9,810	19,644	97,624	5,812	938	3,288	175503.0	174,242	73,849	85,388	14,051	60,739	4,966	3,539	746,555	4,572	5.01	3.11	1.61	0.72	13.1	8.1	1.34	.281	4.38	8.94
17	Astros	3.80	10,141	.503	5,096	5,040	10,141	69,636	1,138	343	2,282	90824.0	86,564	38,344	42,525	8,677	32,135	2,779	2,652	385,643	3,374	6.90	3.18	2.17	0.86	18.1	8.3	1.31	.286	4.21	8.58
18	White Sox	3.80	19,471	.498	9,654	9,714	19,471	95,727	5,938	1,015	3,262	174043.0	171,731	73,542	84,748	13,708	62,269	4,598	2,558	740,433	4,863	4.95	3.22	1.54	0.71	12.9	8.4	1.34	.280	4.38	8.88
19	Mets	3.81	10,134	.484	4,899	5,227	10,134	67,452	1,095	333	2,267	90657.2	86,954	38,359	42,670	8,913	32,342	2,777	3,181	385,500	2,863	6.70	3.21	2.09	0.88	17.5	8.4	1.32	.285	4.24	8.63
20	Guardians	3.83	19,474	.513	9,940	9,443	19,474	100,245	6,084	983	3,112	173963.0	172,564	74,009	85,719	13,311	64,535	4,737	2,837	742,574	4,865	5.19	3.34	1.55	0.69	13.5	8.7	1.36	.285	4.43	8.93
21	Red Sox	3.92	19,463	.518	10,044	9,336	19,463	100,549	5,918	913	3,198	173813.2	174,458	75,758	87,231	13,709	63,295	5,202	2,504	744,221	4,526	5.21	3.28	1.59	0.71	13.5	8.5	1.37	.286	4.52	9.03
22	Padres	3.96	9,008	.468	4,217	4,789	9,008	59,059	668	203	2,177	80555.1	78,147	35,417	39,338	8,376	29,731	2,364	3,093	344,265	2,724	6.60	3.32	1.99	0.94	17.2	8.6	1.34	.285	4.40	8.73
23	Nationals	3.97	9,000	.481	4,331	4,665	9,000	58,430	790	251	2,187	80386.1	78,089	35,494	39,348	8,275	29,542	2,676	2,722	343,729	2,756	6.54	3.31	1.98	0.93	17.0	8.6	1.34	.285	4.41	8.74
24	Phillies	3.99	19,586	.470	9,170	10,339	19,586	99,236	5,747	927	2,941	174604.1	178,383	77,469	89,649	14,196	61,663	5,121	3,589	749,385	4,906	5.12	3.18	1.61	0.73	13.2	8.2	1.37	.288	4.62	9.19
25	Tigers	4.00	19,498	.503	9,763	9,642	19,498	96,630	6,176	902	2,998	173886.0	175,210	77,245	89,205	14,742	64,848	5,246	2,952	746,601	5,041	5.00	3.36	1.49	0.76	12.9	8.7	1.38	.284	4.62	9.07