The Philadelphia Athletics had the highest winning percentage by a team in 1930, winning 66.2 percent of the time.

	TEAM	W%	SEASON	W	L	G	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	AVG	OBP	SLG	OPS
1	Athletics	.662	1930	102	52	154	5,346	951	1,573	320	74	125	895	600	32	531	50	33	6,161	2,416	519	183	.294	.369	.452	.821
2	Senators	.610	1930	94	60	154	5,369	892	1,620	297	98	57	819	533	38	438	101	68	6,113	2,284	452	173	.302	.369	.425	.794
3	Cardinals	.597	1930	92	62	154	5,512	1,004	1,732	373	89	104	942	479	28	496	72		6,204	2,595	566	185	.314	.372	.471	.843
4	Cubs	.584	1930	90	64	156	5,581	998	1,722	305	72	171	940	588	37	635	70		6,354	2,684	548	148	.309	.378	.481	.859
5	Giants	.565	1930	87	67	154	5,553	959	1,769	264	83	143	880	422	21	382	59		6,161	2,628	490	165	.319	.369	.473	.842
6	Robins	.558	1930	86	68	154	5,433	871	1,654	303	73	122	836	481	27	541	53		6,088	2,469	498	147	.304	.364	.454	.818
7	Yankees	.558	1930	86	68	154	5,447	1,062	1,683	298	110	152	985	644	19	569	91	60	6,272	2,657	560	162	.309	.384	.488	.872
8	Indians	.526	1930	81	73	154	5,439	890	1,654	356	60	72	830	481	26	460	51	47	6,120	2,346	488	174	.304	.363	.431	.795
9	Pirates	.519	1930	80	74	154	5,346	891	1,622	285	119	86	844	494	22	449	76		6,058	2,403	490	196	.303	.365	.449	.814
10	Tigers	.487	1930	75	79	154	5,298	783	1,504	298	90	82	728	459	25	507	97	70	5,927	2,228	470	145	.284	.344	.421	.764
11	Braves	.455	1930	70	84	154	5,356	693	1,503	246	78	66	631	332	28	397	69		5,870	2,103	390	154	.281	.326	.393	.719
12	Browns	.416	1930	64	90	154	5,277	751	1,415	288	67	75	691	499	15	547	93	71	5,946	2,062	430	155	.268	.333	.391	.724
13	White Sox	.403	1930	62	92	154	5,416	729	1,497	256	91	63	679	391	32	478	74	39	5,992	2,124	410	153	.276	.329	.392	.721
14	Reds	.383	1930	59	95	154	5,245	665	1,475	265	67	74	625	445	16	489	48		5,880	2,096	406	174	.281	.339	.400	.739
15	Phillies	.338	1930	52	102	156	5,667	944	1,783	345	44	126	884	450	23	459	34		6,288	2,594	515	148	.315	.367	.458	.825
16	Red Sox	.338	1930	52	102	154	5,286	612	1,391	257	67	47	533	356	19	556	42	35	5,805	1,923	371	144	.263	.312	.364	.676