There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

Amana Growth Fund Institutional (AMIGX Quick QuoteAMIGX - Free Report) : 0.64% expense ratio and 0.62% management fee. AMIGX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. AMIGX has achieved five-year annual returns of an astounding 14.15%.

Janus Henderson Global Life Science T (JAGLX Quick QuoteJAGLX - Free Report) is a stand out amongst its peers. JAGLX is a Sector - Health mutual fund, which give investors an opportunity to focus on healthcare, one of the largest sectors of the American economy. With five-year annualized performance of 10.26%, expense ratio of 0.91% and management fee of 0.64%, this diversified fund is an attractive buy with a strong history of performance.

State Street Institutional US Equity Investor (SUSIX Quick QuoteSUSIX - Free Report) . Expense ratio: 0.38%. Management fee: 0.37%. Five year annual return: 10.38%. SUSIX is classified as a Large Cap Blend fund. More often than not, Large Cap Blend mutual funds invest in companies with a market cap of over $10 billion. Buying stakes in bigger companies offer these funds more stability, and are well-suited for investors with a "buy and hold" mindset.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.