The Chicago Cubs had the worst winning percentage by a team in 1966, winning 36.4 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	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Cubs	.364	1966	59	103	162	5,592	644	1,418	203	43	140	603	457	47	998	76	47	6,213	2,127	386	80	37	53	112	.254	.313	.380	.694
2	Mets	.410	1966	66	95	161	5,371	587	1,286	187	35	98	534	446	42	992	55	46	5,951	1,837	320	63	29	44	127	.239	.301	.342	.643
3	Yankees	.440	1966	70	89	160	5,330	611	1,254	182	36	162	569	485	21	817	49	29	5,936	1,994	380	58	42	41	111	.235	.299	.374	.674
4	Red Sox	.444	1966	72	90	162	5,498	655	1,318	228	44	145	617	542	32	1,020	35	24	6,175	2,069	417	65	38	54	131	.240	.310	.376	.686
5	Astros	.444	1966	72	90	163	5,511	612	1,405	203	35	112	570	491	34	885	90	47	6,170	2,014	350	97	37	61	128	.255	.318	.365	.683
6	Senators	.447	1966	71	88	159	5,318	557	1,245	185	40	126	525	450	20	1,069	53	37	5,905	1,888	351	84	33	31	130	.234	.295	.355	.650
7	Athletics	.463	1966	74	86	160	5,328	564	1,259	212	56	70	509	421	26	982	132	50	5,873	1,793	338	71	27	34	100	.236	.294	.337	.631
8	Reds	.475	1966	76	84	160	5,521	692	1,434	232	33	149	651	394	20	877	70	50	6,043	2,179	414	69	39	56	117	.260	.309	.395	.704
9	Angels	.494	1966	80	82	162	5,360	604	1,244	179	54	122	562	525	38	1,062	80	54	6,038	1,897	355	69	46	52	104	.232	.303	.354	.657
10	Indians	.500	1966	81	81	162	5,474	574	1,300	156	25	155	536	450	27	914	53	41	6,040	1,971	336	56	33	55	113	.237	.297	.360	.657
11	Cardinals	.512	1966	83	79	162	5,480	571	1,377	196	61	108	533	345	35	977	144	61	5,963	2,019	365	59	44	51	114	.251	.298	.368	.666
12	White Sox	.512	1966	83	79	163	5,348	574	1,235	193	40	87	524	476	44	872	153	78	6,021	1,769	320	109	44	50	94	.231	.297	.331	.628
13	Braves	.525	1966	85	77	163	5,617	782	1,476	220	32	207	734	512	40	913	59	47	6,286	2,381	459	72	45	75	106	.263	.326	.424	.750
14	Phillies	.537	1966	87	75	162	5,607	696	1,448	224	49	117	628	510	29	969	56	42	6,256	2,121	390	78	32	64	113	.258	.322	.378	.700
15	Tigers	.543	1966	88	74	162	5,507	719	1,383	224	45	179	682	551	33	987	41	34	6,195	2,234	448	67	37	45	128	.251	.321	.406	.727
16	Twins	.549	1966	89	73	162	5,390	663	1,341	219	33	144	611	513	39	844	67	42	6,035	2,058	396	49	44	69	138	.249	.316	.382	.698
17	Pirates	.568	1966	92	70	162	5,676	759	1,586	238	66	158	715	405	35	1,011	64	60	6,229	2,430	462	73	40	75	111	.279	.329	.428	.757
18	Giants	.578	1966	93	68	161	5,539	675	1,373	195	31	181	627	414	32	860	29	30	6,083	2,173	407	70	28	65	142	.248	.303	.392	.695
19	Dodgers	.586	1966	95	67	162	5,471	606	1,399	201	27	108	565	430	49	830	94	64	6,066	1,978	336	84	32	54	117	.256	.314	.362	.675
20	Orioles	.606	1966	97	63	160	5,529	755	1,426	243	35	175	703	514	39	926	55	43	6,199	2,264	453	82	35	59	119	.258	.324	.409	.733